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authorJason A. Donenfeld <Jason@zx2c4.com>2018-11-19 16:57:05 +0100
committerJason A. Donenfeld <Jason@zx2c4.com>2018-11-19 18:07:11 +0100
commita3ff11e6088a16a57ec5b546c2203893db04ab57 (patch)
tree54cfb6e1c1d4f7d1f9484a8ed864f6a301df7e1b /src/crypto/zinc/perlasm
parent872835fc9ca5e2939291fa2d40a4ff2fd021a51e (diff)
chacha20,poly1305: do not use xlate
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Diffstat (limited to 'src/crypto/zinc/perlasm')
-rw-r--r--src/crypto/zinc/perlasm/x86_64-xlate.pl1442
1 files changed, 0 insertions, 1442 deletions
diff --git a/src/crypto/zinc/perlasm/x86_64-xlate.pl b/src/crypto/zinc/perlasm/x86_64-xlate.pl
deleted file mode 100644
index 0fe1516..0000000
--- a/src/crypto/zinc/perlasm/x86_64-xlate.pl
+++ /dev/null
@@ -1,1442 +0,0 @@
-#!/usr/bin/env perl
-# SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
-#
-# Copyright (C) 2017-2018 Samuel Neves <sneves@dei.uc.pt>. All Rights Reserved.
-# Copyright (C) 2006-2017 CRYPTOGAMS by <appro@openssl.org>. All Rights Reserved.
-#
-# This code is taken from the OpenSSL project but the author, Andy Polyakov,
-# has relicensed it under the licenses specified in the SPDX header above.
-# The original headers, including the original license headers, are
-# included below for completeness.
-#
-# ====================================================================
-# Written by Andy Polyakov <appro@openssl.org> for the OpenSSL
-# project. The module is, however, dual licensed under OpenSSL and
-# CRYPTOGAMS licenses depending on where you obtain it. For further
-# details see http://www.openssl.org/~appro/cryptogams/.
-# ====================================================================
-#
-# Ascetic x86_64 AT&T to MASM/NASM assembler translator by <appro>.
-#
-# Why AT&T to MASM and not vice versa? Several reasons. Because AT&T
-# format is way easier to parse. Because it's simpler to "gear" from
-# Unix ABI to Windows one [see cross-reference "card" at the end of
-# file]. Because Linux targets were available first...
-#
-# In addition the script also "distills" code suitable for GNU
-# assembler, so that it can be compiled with more rigid assemblers,
-# such as Solaris /usr/ccs/bin/as.
-#
-# This translator is not designed to convert *arbitrary* assembler
-# code from AT&T format to MASM one. It's designed to convert just
-# enough to provide for dual-ABI OpenSSL modules development...
-# There *are* limitations and you might have to modify your assembler
-# code or this script to achieve the desired result...
-#
-# Currently recognized limitations:
-#
-# - can't use multiple ops per line;
-#
-# Dual-ABI styling rules.
-#
-# 1. Adhere to Unix register and stack layout [see cross-reference
-# ABI "card" at the end for explanation].
-# 2. Forget about "red zone," stick to more traditional blended
-# stack frame allocation. If volatile storage is actually required
-# that is. If not, just leave the stack as is.
-# 3. Functions tagged with ".type name,@function" get crafted with
-# unified Win64 prologue and epilogue automatically. If you want
-# to take care of ABI differences yourself, tag functions as
-# ".type name,@abi-omnipotent" instead.
-# 4. To optimize the Win64 prologue you can specify number of input
-# arguments as ".type name,@function,N." Keep in mind that if N is
-# larger than 6, then you *have to* write "abi-omnipotent" code,
-# because >6 cases can't be addressed with unified prologue.
-# 5. Name local labels as .L*, do *not* use dynamic labels such as 1:
-# (sorry about latter).
-# 6. Don't use [or hand-code with .byte] "rep ret." "ret" mnemonic is
-# required to identify the spots, where to inject Win64 epilogue!
-# But on the pros, it's then prefixed with rep automatically:-)
-# 7. Stick to explicit ip-relative addressing. If you have to use
-# GOTPCREL addressing, stick to mov symbol@GOTPCREL(%rip),%r??.
-# Both are recognized and translated to proper Win64 addressing
-# modes.
-#
-# 8. In order to provide for structured exception handling unified
-# Win64 prologue copies %rsp value to %rax. For further details
-# see SEH paragraph at the end.
-# 9. .init segment is allowed to contain calls to functions only.
-# a. If function accepts more than 4 arguments *and* >4th argument
-# is declared as non 64-bit value, do clear its upper part.
-
-
-use strict;
-
-my $flavour = shift;
-my $output = shift;
-if ($flavour =~ /\./) { $output = $flavour; undef $flavour; }
-
-open STDOUT,">$output" || die "can't open $output: $!"
- if (defined($output));
-
-my $kernel=0; $kernel=1 if ($flavour =~ /linux/);
-my $gas=1; $gas=0 if ($output =~ /\.asm$/);
-my $elf=1; $elf=0 if (!$gas);
-my $win64=0;
-my $prefix="";
-my $decor=".L";
-
-my $masmref=8 + 50727*2**-32; # 8.00.50727 shipped with VS2005
-my $masm=0;
-my $PTR=" PTR";
-
-my $nasmref=2.03;
-my $nasm=0;
-
-if ($flavour eq "mingw64") { $gas=1; $elf=0; $win64=1;
- $prefix=`echo __USER_LABEL_PREFIX__ | $ENV{CC} -E -P -`;
- $prefix =~ s|\R$||; # Better chomp
- }
-elsif ($flavour eq "macosx") { $gas=1; $elf=0; $prefix="_"; $decor="L\$"; }
-elsif ($flavour eq "masm") { $gas=0; $elf=0; $masm=$masmref; $win64=1; $decor="\$L\$"; }
-elsif ($flavour eq "nasm") { $gas=0; $elf=0; $nasm=$nasmref; $win64=1; $decor="\$L\$"; $PTR=""; }
-elsif (!$gas)
-{ if ($ENV{ASM} =~ m/nasm/ && `nasm -v` =~ m/version ([0-9]+)\.([0-9]+)/i)
- { $nasm = $1 + $2*0.01; $PTR=""; }
- elsif (`ml64 2>&1` =~ m/Version ([0-9]+)\.([0-9]+)(\.([0-9]+))?/)
- { $masm = $1 + $2*2**-16 + $4*2**-32; }
- die "no assembler found on %PATH%" if (!($nasm || $masm));
- $win64=1;
- $elf=0;
- $decor="\$L\$";
-}
-
-my $current_segment;
-my $current_function;
-my %globals;
-
-{ package opcode; # pick up opcodes
- sub re {
- my ($class, $line) = @_;
- my $self = {};
- my $ret;
-
- if ($$line =~ /^([a-z][a-z0-9]*)/i) {
- bless $self,$class;
- $self->{op} = $1;
- $ret = $self;
- $$line = substr($$line,@+[0]); $$line =~ s/^\s+//;
-
- undef $self->{sz};
- if ($self->{op} =~ /^(movz)x?([bw]).*/) { # movz is pain...
- $self->{op} = $1;
- $self->{sz} = $2;
- } elsif ($self->{op} =~ /call|jmp/) {
- $self->{sz} = "";
- } elsif ($self->{op} =~ /^p/ && $' !~ /^(ush|op|insrw)/) { # SSEn
- $self->{sz} = "";
- } elsif ($self->{op} =~ /^[vk]/) { # VEX or k* such as kmov
- $self->{sz} = "";
- } elsif ($self->{op} =~ /mov[dq]/ && $$line =~ /%xmm/) {
- $self->{sz} = "";
- } elsif ($self->{op} =~ /([a-z]{3,})([qlwb])$/) {
- $self->{op} = $1;
- $self->{sz} = $2;
- }
- }
- $ret;
- }
- sub size {
- my ($self, $sz) = @_;
- $self->{sz} = $sz if (defined($sz) && !defined($self->{sz}));
- $self->{sz};
- }
- sub out {
- my $self = shift;
- if ($gas) {
- if ($self->{op} eq "movz") { # movz is pain...
- sprintf "%s%s%s",$self->{op},$self->{sz},shift;
- } elsif ($self->{op} =~ /^set/) {
- "$self->{op}";
- } elsif ($self->{op} eq "ret") {
- my $epilogue = "";
- if ($win64 && $current_function->{abi} eq "svr4") {
- $epilogue = "movq 8(%rsp),%rdi\n\t" .
- "movq 16(%rsp),%rsi\n\t";
- }
- $epilogue . "ret";
- } elsif ($self->{op} eq "call" && !$elf && $current_segment eq ".init") {
- ".p2align\t3\n\t.quad";
- } else {
- "$self->{op}$self->{sz}";
- }
- } else {
- $self->{op} =~ s/^movz/movzx/;
- if ($self->{op} eq "ret") {
- $self->{op} = "";
- if ($win64 && $current_function->{abi} eq "svr4") {
- $self->{op} = "mov rdi,QWORD$PTR\[8+rsp\]\t;WIN64 epilogue\n\t".
- "mov rsi,QWORD$PTR\[16+rsp\]\n\t";
- }
- $self->{op} .= "DB\t0F3h,0C3h\t\t;repret";
- } elsif ($self->{op} =~ /^(pop|push)f/) {
- $self->{op} .= $self->{sz};
- } elsif ($self->{op} eq "call" && $current_segment eq ".CRT\$XCU") {
- $self->{op} = "\tDQ";
- }
- $self->{op};
- }
- }
- sub mnemonic {
- my ($self, $op) = @_;
- $self->{op}=$op if (defined($op));
- $self->{op};
- }
-}
-{ package const; # pick up constants, which start with $
- sub re {
- my ($class, $line) = @_;
- my $self = {};
- my $ret;
-
- if ($$line =~ /^\$([^,]+)/) {
- bless $self, $class;
- $self->{value} = $1;
- $ret = $self;
- $$line = substr($$line,@+[0]); $$line =~ s/^\s+//;
- }
- $ret;
- }
- sub out {
- my $self = shift;
-
- $self->{value} =~ s/\b(0b[0-1]+)/oct($1)/eig;
- if ($gas) {
- # Solaris /usr/ccs/bin/as can't handle multiplications
- # in $self->{value}
- my $value = $self->{value};
- no warnings; # oct might complain about overflow, ignore here...
- $value =~ s/(?<![\w\$\.])(0x?[0-9a-f]+)/oct($1)/egi;
- if ($value =~ s/([0-9]+\s*[\*\/\%]\s*[0-9]+)/eval($1)/eg) {
- $self->{value} = $value;
- }
- sprintf "\$%s",$self->{value};
- } else {
- my $value = $self->{value};
- $value =~ s/0x([0-9a-f]+)/0$1h/ig if ($masm);
- sprintf "%s",$value;
- }
- }
-}
-{ package ea; # pick up effective addresses: expr(%reg,%reg,scale)
-
- my %szmap = ( b=>"BYTE$PTR", w=>"WORD$PTR",
- l=>"DWORD$PTR", d=>"DWORD$PTR",
- q=>"QWORD$PTR", o=>"OWORD$PTR",
- x=>"XMMWORD$PTR", y=>"YMMWORD$PTR",
- z=>"ZMMWORD$PTR" ) if (!$gas);
-
- sub re {
- my ($class, $line, $opcode) = @_;
- my $self = {};
- my $ret;
-
- # optional * ----vvv--- appears in indirect jmp/call
- if ($$line =~ /^(\*?)([^\(,]*)\(([%\w,]+)\)((?:{[^}]+})*)/) {
- bless $self, $class;
- $self->{asterisk} = $1;
- $self->{label} = $2;
- ($self->{base},$self->{index},$self->{scale})=split(/,/,$3);
- $self->{scale} = 1 if (!defined($self->{scale}));
- $self->{opmask} = $4;
- $ret = $self;
- $$line = substr($$line,@+[0]); $$line =~ s/^\s+//;
-
- if ($win64 && $self->{label} =~ s/\@GOTPCREL//) {
- die if ($opcode->mnemonic() ne "mov");
- $opcode->mnemonic("lea");
- }
- $self->{base} =~ s/^%//;
- $self->{index} =~ s/^%// if (defined($self->{index}));
- $self->{opcode} = $opcode;
- }
- $ret;
- }
- sub size {}
- sub out {
- my ($self, $sz) = @_;
-
- $self->{label} =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei;
- $self->{label} =~ s/\.L/$decor/g;
-
- # Silently convert all EAs to 64-bit. This is required for
- # elder GNU assembler and results in more compact code,
- # *but* most importantly AES module depends on this feature!
- $self->{index} =~ s/^[er](.?[0-9xpi])[d]?$/r\1/;
- $self->{base} =~ s/^[er](.?[0-9xpi])[d]?$/r\1/;
-
- # Solaris /usr/ccs/bin/as can't handle multiplications
- # in $self->{label}...
- use integer;
- $self->{label} =~ s/(?<![\w\$\.])(0x?[0-9a-f]+)/oct($1)/egi;
- $self->{label} =~ s/\b([0-9]+\s*[\*\/\%]\s*[0-9]+)\b/eval($1)/eg;
-
- # Some assemblers insist on signed presentation of 32-bit
- # offsets, but sign extension is a tricky business in perl...
- if ((1<<31)<<1) {
- $self->{label} =~ s/\b([0-9]+)\b/$1<<32>>32/eg;
- } else {
- $self->{label} =~ s/\b([0-9]+)\b/$1>>0/eg;
- }
-
- # if base register is %rbp or %r13, see if it's possible to
- # flip base and index registers [for better performance]
- if (!$self->{label} && $self->{index} && $self->{scale}==1 &&
- $self->{base} =~ /(rbp|r13)/) {
- $self->{base} = $self->{index}; $self->{index} = $1;
- }
-
- if ($gas) {
- $self->{label} =~ s/^___imp_/__imp__/ if ($flavour eq "mingw64");
-
- if (defined($self->{index})) {
- sprintf "%s%s(%s,%%%s,%d)%s",
- $self->{asterisk},$self->{label},
- $self->{base}?"%$self->{base}":"",
- $self->{index},$self->{scale},
- $self->{opmask};
- } else {
- sprintf "%s%s(%%%s)%s", $self->{asterisk},$self->{label},
- $self->{base},$self->{opmask};
- }
- } else {
- $self->{label} =~ s/\./\$/g;
- $self->{label} =~ s/(?<![\w\$\.])0x([0-9a-f]+)/0$1h/ig;
- $self->{label} = "($self->{label})" if ($self->{label} =~ /[\*\+\-\/]/);
-
- my $mnemonic = $self->{opcode}->mnemonic();
- ($self->{asterisk}) && ($sz="q") ||
- ($mnemonic =~ /^v?mov([qd])$/) && ($sz=$1) ||
- ($mnemonic =~ /^v?pinsr([qdwb])$/) && ($sz=$1) ||
- ($mnemonic =~ /^vpbroadcast([qdwb])$/) && ($sz=$1) ||
- ($mnemonic =~ /^v(?!perm)[a-z]+[fi]128$/) && ($sz="x");
-
- $self->{opmask} =~ s/%(k[0-7])/$1/;
-
- if (defined($self->{index})) {
- sprintf "%s[%s%s*%d%s]%s",$szmap{$sz},
- $self->{label}?"$self->{label}+":"",
- $self->{index},$self->{scale},
- $self->{base}?"+$self->{base}":"",
- $self->{opmask};
- } elsif ($self->{base} eq "rip") {
- sprintf "%s[%s]",$szmap{$sz},$self->{label};
- } else {
- sprintf "%s[%s%s]%s", $szmap{$sz},
- $self->{label}?"$self->{label}+":"",
- $self->{base},$self->{opmask};
- }
- }
- }
-}
-{ package register; # pick up registers, which start with %.
- sub re {
- my ($class, $line, $opcode) = @_;
- my $self = {};
- my $ret;
-
- # optional * ----vvv--- appears in indirect jmp/call
- if ($$line =~ /^(\*?)%(\w+)((?:{[^}]+})*)/) {
- bless $self,$class;
- $self->{asterisk} = $1;
- $self->{value} = $2;
- $self->{opmask} = $3;
- $opcode->size($self->size());
- $ret = $self;
- $$line = substr($$line,@+[0]); $$line =~ s/^\s+//;
- }
- $ret;
- }
- sub size {
- my $self = shift;
- my $ret;
-
- if ($self->{value} =~ /^r[\d]+b$/i) { $ret="b"; }
- elsif ($self->{value} =~ /^r[\d]+w$/i) { $ret="w"; }
- elsif ($self->{value} =~ /^r[\d]+d$/i) { $ret="l"; }
- elsif ($self->{value} =~ /^r[\w]+$/i) { $ret="q"; }
- elsif ($self->{value} =~ /^[a-d][hl]$/i){ $ret="b"; }
- elsif ($self->{value} =~ /^[\w]{2}l$/i) { $ret="b"; }
- elsif ($self->{value} =~ /^[\w]{2}$/i) { $ret="w"; }
- elsif ($self->{value} =~ /^e[a-z]{2}$/i){ $ret="l"; }
-
- $ret;
- }
- sub out {
- my $self = shift;
- if ($gas) { sprintf "%s%%%s%s", $self->{asterisk},
- $self->{value},
- $self->{opmask}; }
- else { $self->{opmask} =~ s/%(k[0-7])/$1/;
- $self->{value}.$self->{opmask}; }
- }
-}
-{ package label; # pick up labels, which end with :
- sub re {
- my ($class, $line) = @_;
- my $self = {};
- my $ret;
-
- if ($$line =~ /(^[\.\w]+)\:/) {
- bless $self,$class;
- $self->{value} = $1;
- $ret = $self;
- $$line = substr($$line,@+[0]); $$line =~ s/^\s+//;
-
- $self->{value} =~ s/^\.L/$decor/;
- }
- $ret;
- }
- sub out {
- my $self = shift;
-
- if ($gas) {
- my $func = ($globals{$self->{value}} or $self->{value}) . ":";
- if ($win64 && $current_function->{name} eq $self->{value}
- && $current_function->{abi} eq "svr4") {
- $func .= "\n";
- $func .= " movq %rdi,8(%rsp)\n";
- $func .= " movq %rsi,16(%rsp)\n";
- $func .= " movq %rsp,%rax\n";
- $func .= "${decor}SEH_begin_$current_function->{name}:\n";
- my $narg = $current_function->{narg};
- $narg=6 if (!defined($narg));
- $func .= " movq %rcx,%rdi\n" if ($narg>0);
- $func .= " movq %rdx,%rsi\n" if ($narg>1);
- $func .= " movq %r8,%rdx\n" if ($narg>2);
- $func .= " movq %r9,%rcx\n" if ($narg>3);
- $func .= " movq 40(%rsp),%r8\n" if ($narg>4);
- $func .= " movq 48(%rsp),%r9\n" if ($narg>5);
- }
- $func;
- } elsif ($self->{value} ne "$current_function->{name}") {
- # Make all labels in masm global.
- $self->{value} .= ":" if ($masm);
- $self->{value} . ":";
- } elsif ($win64 && $current_function->{abi} eq "svr4") {
- my $func = "$current_function->{name}" .
- ($nasm ? ":" : "\tPROC $current_function->{scope}") .
- "\n";
- $func .= " mov QWORD$PTR\[8+rsp\],rdi\t;WIN64 prologue\n";
- $func .= " mov QWORD$PTR\[16+rsp\],rsi\n";
- $func .= " mov rax,rsp\n";
- $func .= "${decor}SEH_begin_$current_function->{name}:";
- $func .= ":" if ($masm);
- $func .= "\n";
- my $narg = $current_function->{narg};
- $narg=6 if (!defined($narg));
- $func .= " mov rdi,rcx\n" if ($narg>0);
- $func .= " mov rsi,rdx\n" if ($narg>1);
- $func .= " mov rdx,r8\n" if ($narg>2);
- $func .= " mov rcx,r9\n" if ($narg>3);
- $func .= " mov r8,QWORD$PTR\[40+rsp\]\n" if ($narg>4);
- $func .= " mov r9,QWORD$PTR\[48+rsp\]\n" if ($narg>5);
- $func .= "\n";
- } else {
- "$current_function->{name}".
- ($nasm ? ":" : "\tPROC $current_function->{scope}");
- }
- }
-}
-{ package expr; # pick up expressions
- sub re {
- my ($class, $line, $opcode) = @_;
- my $self = {};
- my $ret;
-
- if ($$line =~ /(^[^,]+)/) {
- bless $self,$class;
- $self->{value} = $1;
- $ret = $self;
- $$line = substr($$line,@+[0]); $$line =~ s/^\s+//;
-
- $self->{value} =~ s/\@PLT// if (!$elf);
- $self->{value} =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei;
- $self->{value} =~ s/\.L/$decor/g;
- $self->{opcode} = $opcode;
- }
- $ret;
- }
- sub out {
- my $self = shift;
- if ($nasm && $self->{opcode}->mnemonic()=~m/^j(?![re]cxz)/) {
- "NEAR ".$self->{value};
- } else {
- $self->{value};
- }
- }
-}
-{ package cfi_directive;
- # CFI directives annotate instructions that are significant for
- # stack unwinding procedure compliant with DWARF specification,
- # see http://dwarfstd.org/. Besides naturally expected for this
- # script platform-specific filtering function, this module adds
- # three auxiliary synthetic directives not recognized by [GNU]
- # assembler:
- #
- # - .cfi_push to annotate push instructions in prologue, which
- # translates to .cfi_adjust_cfa_offset (if needed) and
- # .cfi_offset;
- # - .cfi_pop to annotate pop instructions in epilogue, which
- # translates to .cfi_adjust_cfa_offset (if needed) and
- # .cfi_restore;
- # - [and most notably] .cfi_cfa_expression which encodes
- # DW_CFA_def_cfa_expression and passes it to .cfi_escape as
- # byte vector;
- #
- # CFA expressions were introduced in DWARF specification version
- # 3 and describe how to deduce CFA, Canonical Frame Address. This
- # becomes handy if your stack frame is variable and you can't
- # spare register for [previous] frame pointer. Suggested directive
- # syntax is made-up mix of DWARF operator suffixes [subset of]
- # and references to registers with optional bias. Following example
- # describes offloaded *original* stack pointer at specific offset
- # from *current* stack pointer:
- #
- # .cfi_cfa_expression %rsp+40,deref,+8
- #
- # Final +8 has everything to do with the fact that CFA is defined
- # as reference to top of caller's stack, and on x86_64 call to
- # subroutine pushes 8-byte return address. In other words original
- # stack pointer upon entry to a subroutine is 8 bytes off from CFA.
-
- # Below constants are taken from "DWARF Expressions" section of the
- # DWARF specification, section is numbered 7.7 in versions 3 and 4.
- my %DW_OP_simple = ( # no-arg operators, mapped directly
- deref => 0x06, dup => 0x12,
- drop => 0x13, over => 0x14,
- pick => 0x15, swap => 0x16,
- rot => 0x17, xderef => 0x18,
-
- abs => 0x19, and => 0x1a,
- div => 0x1b, minus => 0x1c,
- mod => 0x1d, mul => 0x1e,
- neg => 0x1f, not => 0x20,
- or => 0x21, plus => 0x22,
- shl => 0x24, shr => 0x25,
- shra => 0x26, xor => 0x27,
- );
-
- my %DW_OP_complex = ( # used in specific subroutines
- constu => 0x10, # uleb128
- consts => 0x11, # sleb128
- plus_uconst => 0x23, # uleb128
- lit0 => 0x30, # add 0-31 to opcode
- reg0 => 0x50, # add 0-31 to opcode
- breg0 => 0x70, # add 0-31 to opcole, sleb128
- regx => 0x90, # uleb28
- fbreg => 0x91, # sleb128
- bregx => 0x92, # uleb128, sleb128
- piece => 0x93, # uleb128
- );
-
- # Following constants are defined in x86_64 ABI supplement, for
- # example available at https://www.uclibc.org/docs/psABI-x86_64.pdf,
- # see section 3.7 "Stack Unwind Algorithm".
- my %DW_reg_idx = (
- "%rax"=>0, "%rdx"=>1, "%rcx"=>2, "%rbx"=>3,
- "%rsi"=>4, "%rdi"=>5, "%rbp"=>6, "%rsp"=>7,
- "%r8" =>8, "%r9" =>9, "%r10"=>10, "%r11"=>11,
- "%r12"=>12, "%r13"=>13, "%r14"=>14, "%r15"=>15
- );
-
- my ($cfa_reg, $cfa_rsp);
-
- # [us]leb128 format is variable-length integer representation base
- # 2^128, with most significant bit of each byte being 0 denoting
- # *last* most significant digit. See "Variable Length Data" in the
- # DWARF specification, numbered 7.6 at least in versions 3 and 4.
- sub sleb128 {
- use integer; # get right shift extend sign
-
- my $val = shift;
- my $sign = ($val < 0) ? -1 : 0;
- my @ret = ();
-
- while(1) {
- push @ret, $val&0x7f;
-
- # see if remaining bits are same and equal to most
- # significant bit of the current digit, if so, it's
- # last digit...
- last if (($val>>6) == $sign);
-
- @ret[-1] |= 0x80;
- $val >>= 7;
- }
-
- return @ret;
- }
- sub uleb128 {
- my $val = shift;
- my @ret = ();
-
- while(1) {
- push @ret, $val&0x7f;
-
- # see if it's last significant digit...
- last if (($val >>= 7) == 0);
-
- @ret[-1] |= 0x80;
- }
-
- return @ret;
- }
- sub const {
- my $val = shift;
-
- if ($val >= 0 && $val < 32) {
- return ($DW_OP_complex{lit0}+$val);
- }
- return ($DW_OP_complex{consts}, sleb128($val));
- }
- sub reg {
- my $val = shift;
-
- return if ($val !~ m/^(%r\w+)(?:([\+\-])((?:0x)?[0-9a-f]+))?/);
-
- my $reg = $DW_reg_idx{$1};
- my $off = eval ("0 $2 $3");
-
- return (($DW_OP_complex{breg0} + $reg), sleb128($off));
- # Yes, we use DW_OP_bregX+0 to push register value and not
- # DW_OP_regX, because latter would require even DW_OP_piece,
- # which would be a waste under the circumstances. If you have
- # to use DWP_OP_reg, use "regx:N"...
- }
- sub cfa_expression {
- my $line = shift;
- my @ret;
-
- foreach my $token (split(/,\s*/,$line)) {
- if ($token =~ /^%r/) {
- push @ret,reg($token);
- } elsif ($token =~ /((?:0x)?[0-9a-f]+)\((%r\w+)\)/) {
- push @ret,reg("$2+$1");
- } elsif ($token =~ /(\w+):(\-?(?:0x)?[0-9a-f]+)(U?)/i) {
- my $i = 1*eval($2);
- push @ret,$DW_OP_complex{$1}, ($3 ? uleb128($i) : sleb128($i));
- } elsif (my $i = 1*eval($token) or $token eq "0") {
- if ($token =~ /^\+/) {
- push @ret,$DW_OP_complex{plus_uconst},uleb128($i);
- } else {
- push @ret,const($i);
- }
- } else {
- push @ret,$DW_OP_simple{$token};
- }
- }
-
- # Finally we return DW_CFA_def_cfa_expression, 15, followed by
- # length of the expression and of course the expression itself.
- return (15,scalar(@ret),@ret);
- }
- sub re {
- my ($class, $line) = @_;
- my $self = {};
- my $ret;
-
- if ($$line =~ s/^\s*\.cfi_(\w+)\s*//) {
- bless $self,$class;
- $ret = $self;
- undef $self->{value};
- my $dir = $1;
-
- SWITCH: for ($dir) {
- # What is $cfa_rsp? Effectively it's difference between %rsp
- # value and current CFA, Canonical Frame Address, which is
- # why it starts with -8. Recall that CFA is top of caller's
- # stack...
- /startproc/ && do { ($cfa_reg, $cfa_rsp) = ("%rsp", -8); last; };
- /endproc/ && do { ($cfa_reg, $cfa_rsp) = ("%rsp", 0); last; };
- /def_cfa_register/
- && do { $cfa_reg = $$line; last; };
- /def_cfa_offset/
- && do { $cfa_rsp = -1*eval($$line) if ($cfa_reg eq "%rsp");
- last;
- };
- /adjust_cfa_offset/
- && do { $cfa_rsp -= 1*eval($$line) if ($cfa_reg eq "%rsp");
- last;
- };
- /def_cfa/ && do { if ($$line =~ /(%r\w+)\s*,\s*(.+)/) {
- $cfa_reg = $1;
- $cfa_rsp = -1*eval($2) if ($cfa_reg eq "%rsp");
- }
- last;
- };
- /push/ && do { $dir = undef;
- $cfa_rsp -= 8;
- if ($cfa_reg eq "%rsp") {
- $self->{value} = ".cfi_adjust_cfa_offset\t8\n";
- }
- $self->{value} .= ".cfi_offset\t$$line,$cfa_rsp";
- last;
- };
- /pop/ && do { $dir = undef;
- $cfa_rsp += 8;
- if ($cfa_reg eq "%rsp") {
- $self->{value} = ".cfi_adjust_cfa_offset\t-8\n";
- }
- $self->{value} .= ".cfi_restore\t$$line";
- last;
- };
- /cfa_expression/
- && do { $dir = undef;
- $self->{value} = ".cfi_escape\t" .
- join(",", map(sprintf("0x%02x", $_),
- cfa_expression($$line)));
- last;
- };
- }
-
- $self->{value} = ".cfi_$dir\t$$line" if ($dir);
-
- $$line = "";
- }
-
- return $ret;
- }
- sub out {
- my $self = shift;
- return ($elf ? $self->{value} : undef);
- }
-}
-{ package directive; # pick up directives, which start with .
- sub re {
- my ($class, $line) = @_;
- my $self = {};
- my $ret;
- my $dir;
-
- # chain-call to cfi_directive
- $ret = cfi_directive->re($line) and return $ret;
-
- if ($$line =~ /^\s*(\.\w+)/) {
- bless $self,$class;
- $dir = $1;
- $ret = $self;
- undef $self->{value};
- $$line = substr($$line,@+[0]); $$line =~ s/^\s+//;
-
- SWITCH: for ($dir) {
- /\.global|\.globl|\.extern/
- && do { $globals{$$line} = $prefix . $$line;
- $$line = $globals{$$line} if ($prefix);
- last;
- };
- /\.type/ && do { my ($sym,$type,$narg) = split(',',$$line);
- if ($type eq "\@function") {
- undef $current_function;
- $current_function->{name} = $sym;
- $current_function->{abi} = "svr4";
- $current_function->{narg} = $narg;
- $current_function->{scope} = defined($globals{$sym})?"PUBLIC":"PRIVATE";
- } elsif ($type eq "\@abi-omnipotent") {
- undef $current_function;
- $current_function->{name} = $sym;
- $current_function->{scope} = defined($globals{$sym})?"PUBLIC":"PRIVATE";
- }
- $$line =~ s/\@abi\-omnipotent/\@function/;
- $$line =~ s/\@function.*/\@function/;
- last;
- };
- /\.asciz/ && do { if ($$line =~ /^"(.*)"$/) {
- $dir = ".byte";
- $$line = join(",",unpack("C*",$1),0);
- }
- last;
- };
- /\.rva|\.long|\.quad/
- && do { $$line =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei;
- $$line =~ s/\.L/$decor/g;
- last;
- };
- }
-
- if ($gas) {
- $self->{value} = $dir . "\t" . $$line;
-
- if ($dir =~ /\.extern/) {
- $self->{value} = ""; # swallow extern
- } elsif (!$elf && $dir =~ /\.type/) {
- $self->{value} = "";
- $self->{value} = ".def\t" . ($globals{$1} or $1) . ";\t" .
- (defined($globals{$1})?".scl 2;":".scl 3;") .
- "\t.type 32;\t.endef"
- if ($win64 && $$line =~ /([^,]+),\@function/);
- } elsif (!$elf && $dir =~ /\.size/) {
- $self->{value} = "";
- if (defined($current_function)) {
- $self->{value} .= "${decor}SEH_end_$current_function->{name}:"
- if ($win64 && $current_function->{abi} eq "svr4");
- undef $current_function;
- }
- } elsif (!$elf && $dir =~ /\.align/) {
- $self->{value} = ".p2align\t" . (log($$line)/log(2));
- } elsif ($dir eq ".section") {
- $current_segment=$$line;
- if (!$elf && $current_segment eq ".init") {
- if ($flavour eq "macosx") { $self->{value} = ".mod_init_func"; }
- elsif ($flavour eq "mingw64") { $self->{value} = ".section\t.ctors"; }
- }
- } elsif ($dir =~ /\.(text|data)/) {
- $current_segment=".$1";
- } elsif ($dir =~ /\.hidden/) {
- if ($flavour eq "macosx") { $self->{value} = ".private_extern\t$prefix$$line"; }
- elsif ($flavour eq "mingw64") { $self->{value} = ""; }
- } elsif ($dir =~ /\.comm/) {
- $self->{value} = "$dir\t$prefix$$line";
- $self->{value} =~ s|,([0-9]+),([0-9]+)$|",$1,".log($2)/log(2)|e if ($flavour eq "macosx");
- }
- $$line = "";
- return $self;
- }
-
- # non-gas case or nasm/masm
- SWITCH: for ($dir) {
- /\.text/ && do { my $v=undef;
- if ($nasm) {
- $v="section .text code align=64\n";
- } else {
- $v="$current_segment\tENDS\n" if ($current_segment);
- $current_segment = ".text\$";
- $v.="$current_segment\tSEGMENT ";
- $v.=$masm>=$masmref ? "ALIGN(256)" : "PAGE";
- $v.=" 'CODE'";
- }
- $self->{value} = $v;
- last;
- };
- /\.data/ && do { my $v=undef;
- if ($nasm) {
- $v="section .data data align=8\n";
- } else {
- $v="$current_segment\tENDS\n" if ($current_segment);
- $current_segment = "_DATA";
- $v.="$current_segment\tSEGMENT";
- }
- $self->{value} = $v;
- last;
- };
- /\.section/ && do { my $v=undef;
- $$line =~ s/([^,]*).*/$1/;
- $$line = ".CRT\$XCU" if ($$line eq ".init");
- if ($nasm) {
- $v="section $$line";
- if ($$line=~/\.([px])data/) {
- $v.=" rdata align=";
- $v.=$1 eq "p"? 4 : 8;
- } elsif ($$line=~/\.CRT\$/i) {
- $v.=" rdata align=8";
- }
- } else {
- $v="$current_segment\tENDS\n" if ($current_segment);
- $v.="$$line\tSEGMENT";
- if ($$line=~/\.([px])data/) {
- $v.=" READONLY";
- $v.=" ALIGN(".($1 eq "p" ? 4 : 8).")" if ($masm>=$masmref);
- } elsif ($$line=~/\.CRT\$/i) {
- $v.=" READONLY ";
- $v.=$masm>=$masmref ? "ALIGN(8)" : "DWORD";
- }
- }
- $current_segment = $$line;
- $self->{value} = $v;
- last;
- };
- /\.extern/ && do { $self->{value} = "EXTERN\t".$$line;
- $self->{value} .= ":NEAR" if ($masm);
- last;
- };
- /\.globl|.global/
- && do { $self->{value} = $masm?"PUBLIC":"global";
- $self->{value} .= "\t".$$line;
- last;
- };
- /\.size/ && do { if (defined($current_function)) {
- undef $self->{value};
- if ($current_function->{abi} eq "svr4") {
- $self->{value}="${decor}SEH_end_$current_function->{name}:";
- $self->{value}.=":\n" if($masm);
- }
- $self->{value}.="$current_function->{name}\tENDP" if($masm && $current_function->{name});
- undef $current_function;
- }
- last;
- };
- /\.align/ && do { my $max = ($masm && $masm>=$masmref) ? 256 : 4096;
- $self->{value} = "ALIGN\t".($$line>$max?$max:$$line);
- last;
- };
- /\.(value|long|rva|quad)/
- && do { my $sz = substr($1,0,1);
- my @arr = split(/,\s*/,$$line);
- my $last = pop(@arr);
- my $conv = sub { my $var=shift;
- $var=~s/^(0b[0-1]+)/oct($1)/eig;
- $var=~s/^0x([0-9a-f]+)/0$1h/ig if ($masm);
- if ($sz eq "D" && ($current_segment=~/.[px]data/ || $dir eq ".rva"))
- { $var=~s/^([_a-z\$\@][_a-z0-9\$\@]*)/$nasm?"$1 wrt ..imagebase":"imagerel $1"/egi; }
- $var;
- };
-
- $sz =~ tr/bvlrq/BWDDQ/;
- $self->{value} = "\tD$sz\t";
- for (@arr) { $self->{value} .= &$conv($_).","; }
- $self->{value} .= &$conv($last);
- last;
- };
- /\.byte/ && do { my @str=split(/,\s*/,$$line);
- map(s/(0b[0-1]+)/oct($1)/eig,@str);
- map(s/0x([0-9a-f]+)/0$1h/ig,@str) if ($masm);
- while ($#str>15) {
- $self->{value}.="DB\t"
- .join(",",@str[0..15])."\n";
- foreach (0..15) { shift @str; }
- }
- $self->{value}.="DB\t"
- .join(",",@str) if (@str);
- last;
- };
- /\.comm/ && do { my @str=split(/,\s*/,$$line);
- my $v=undef;
- if ($nasm) {
- $v.="common $prefix@str[0] @str[1]";
- } else {
- $v="$current_segment\tENDS\n" if ($current_segment);
- $current_segment = "_DATA";
- $v.="$current_segment\tSEGMENT\n";
- $v.="COMM @str[0]:DWORD:".@str[1]/4;
- }
- $self->{value} = $v;
- last;
- };
- }
- $$line = "";
- }
-
- $ret;
- }
- sub out {
- my $self = shift;
- $self->{value};
- }
-}
-
-# Upon initial x86_64 introduction SSE>2 extensions were not introduced
-# yet. In order not to be bothered by tracing exact assembler versions,
-# but at the same time to provide a bare security minimum of AES-NI, we
-# hard-code some instructions. Extensions past AES-NI on the other hand
-# are traced by examining assembler version in individual perlasm
-# modules...
-
-my %regrm = ( "%eax"=>0, "%ecx"=>1, "%edx"=>2, "%ebx"=>3,
- "%esp"=>4, "%ebp"=>5, "%esi"=>6, "%edi"=>7 );
-
-sub rex {
- my $opcode=shift;
- my ($dst,$src,$rex)=@_;
-
- $rex|=0x04 if($dst>=8);
- $rex|=0x01 if($src>=8);
- push @$opcode,($rex|0x40) if ($rex);
-}
-
-my $movq = sub { # elderly gas can't handle inter-register movq
- my $arg = shift;
- my @opcode=(0x66);
- if ($arg =~ /%xmm([0-9]+),\s*%r(\w+)/) {
- my ($src,$dst)=($1,$2);
- if ($dst !~ /[0-9]+/) { $dst = $regrm{"%e$dst"}; }
- rex(\@opcode,$src,$dst,0x8);
- push @opcode,0x0f,0x7e;
- push @opcode,0xc0|(($src&7)<<3)|($dst&7); # ModR/M
- @opcode;
- } elsif ($arg =~ /%r(\w+),\s*%xmm([0-9]+)/) {
- my ($src,$dst)=($2,$1);
- if ($dst !~ /[0-9]+/) { $dst = $regrm{"%e$dst"}; }
- rex(\@opcode,$src,$dst,0x8);
- push @opcode,0x0f,0x6e;
- push @opcode,0xc0|(($src&7)<<3)|($dst&7); # ModR/M
- @opcode;
- } else {
- ();
- }
-};
-
-my $pextrd = sub {
- if (shift =~ /\$([0-9]+),\s*%xmm([0-9]+),\s*(%\w+)/) {
- my @opcode=(0x66);
- my $imm=$1;
- my $src=$2;
- my $dst=$3;
- if ($dst =~ /%r([0-9]+)d/) { $dst = $1; }
- elsif ($dst =~ /%e/) { $dst = $regrm{$dst}; }
- rex(\@opcode,$src,$dst);
- push @opcode,0x0f,0x3a,0x16;
- push @opcode,0xc0|(($src&7)<<3)|($dst&7); # ModR/M
- push @opcode,$imm;
- @opcode;
- } else {
- ();
- }
-};
-
-my $pinsrd = sub {
- if (shift =~ /\$([0-9]+),\s*(%\w+),\s*%xmm([0-9]+)/) {
- my @opcode=(0x66);
- my $imm=$1;
- my $src=$2;
- my $dst=$3;
- if ($src =~ /%r([0-9]+)/) { $src = $1; }
- elsif ($src =~ /%e/) { $src = $regrm{$src}; }
- rex(\@opcode,$dst,$src);
- push @opcode,0x0f,0x3a,0x22;
- push @opcode,0xc0|(($dst&7)<<3)|($src&7); # ModR/M
- push @opcode,$imm;
- @opcode;
- } else {
- ();
- }
-};
-
-my $pshufb = sub {
- if (shift =~ /%xmm([0-9]+),\s*%xmm([0-9]+)/) {
- my @opcode=(0x66);
- rex(\@opcode,$2,$1);
- push @opcode,0x0f,0x38,0x00;
- push @opcode,0xc0|($1&7)|(($2&7)<<3); # ModR/M
- @opcode;
- } else {
- ();
- }
-};
-
-my $palignr = sub {
- if (shift =~ /\$([0-9]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) {
- my @opcode=(0x66);
- rex(\@opcode,$3,$2);
- push @opcode,0x0f,0x3a,0x0f;
- push @opcode,0xc0|($2&7)|(($3&7)<<3); # ModR/M
- push @opcode,$1;
- @opcode;
- } else {
- ();
- }
-};
-
-my $pclmulqdq = sub {
- if (shift =~ /\$([x0-9a-f]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) {
- my @opcode=(0x66);
- rex(\@opcode,$3,$2);
- push @opcode,0x0f,0x3a,0x44;
- push @opcode,0xc0|($2&7)|(($3&7)<<3); # ModR/M
- my $c=$1;
- push @opcode,$c=~/^0/?oct($c):$c;
- @opcode;
- } else {
- ();
- }
-};
-
-my $rdrand = sub {
- if (shift =~ /%[er](\w+)/) {
- my @opcode=();
- my $dst=$1;
- if ($dst !~ /[0-9]+/) { $dst = $regrm{"%e$dst"}; }
- rex(\@opcode,0,$dst,8);
- push @opcode,0x0f,0xc7,0xf0|($dst&7);
- @opcode;
- } else {
- ();
- }
-};
-
-my $rdseed = sub {
- if (shift =~ /%[er](\w+)/) {
- my @opcode=();
- my $dst=$1;
- if ($dst !~ /[0-9]+/) { $dst = $regrm{"%e$dst"}; }
- rex(\@opcode,0,$dst,8);
- push @opcode,0x0f,0xc7,0xf8|($dst&7);
- @opcode;
- } else {
- ();
- }
-};
-
-# Not all AVX-capable assemblers recognize AMD XOP extension. Since we
-# are using only two instructions hand-code them in order to be excused
-# from chasing assembler versions...
-
-sub rxb {
- my $opcode=shift;
- my ($dst,$src1,$src2,$rxb)=@_;
-
- $rxb|=0x7<<5;
- $rxb&=~(0x04<<5) if($dst>=8);
- $rxb&=~(0x01<<5) if($src1>=8);
- $rxb&=~(0x02<<5) if($src2>=8);
- push @$opcode,$rxb;
-}
-
-my $vprotd = sub {
- if (shift =~ /\$([x0-9a-f]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) {
- my @opcode=(0x8f);
- rxb(\@opcode,$3,$2,-1,0x08);
- push @opcode,0x78,0xc2;
- push @opcode,0xc0|($2&7)|(($3&7)<<3); # ModR/M
- my $c=$1;
- push @opcode,$c=~/^0/?oct($c):$c;
- @opcode;
- } else {
- ();
- }
-};
-
-my $vprotq = sub {
- if (shift =~ /\$([x0-9a-f]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) {
- my @opcode=(0x8f);
- rxb(\@opcode,$3,$2,-1,0x08);
- push @opcode,0x78,0xc3;
- push @opcode,0xc0|($2&7)|(($3&7)<<3); # ModR/M
- my $c=$1;
- push @opcode,$c=~/^0/?oct($c):$c;
- @opcode;
- } else {
- ();
- }
-};
-
-# Intel Control-flow Enforcement Technology extension. All functions and
-# indirect branch targets will have to start with this instruction...
-
-my $endbranch = sub {
- (0xf3,0x0f,0x1e,0xfa);
-};
-
-########################################################################
-
-if ($nasm) {
- print <<___;
-default rel
-%define XMMWORD
-%define YMMWORD
-%define ZMMWORD
-___
-} elsif ($masm) {
- print <<___;
-OPTION DOTNAME
-___
-}
-while(defined(my $line=<>)) {
-
- $line =~ s|\R$||; # Better chomp
-
- $line =~ s|[#!](?!include)(?!ifdef)(?!endif).*$||; # get rid of asm-style comments...
- $line =~ s|/\*.*\*/||; # ... and C-style comments...
- $line =~ s|^\s+||; # ... and skip white spaces in beginning
- $line =~ s|\s+$||; # ... and at the end
-
- if (my $label=label->re(\$line)) { print $label->out(); }
-
- if (my $directive=directive->re(\$line)) {
- printf "%s",$directive->out();
- } elsif (my $opcode=opcode->re(\$line)) {
- my $asm = eval("\$".$opcode->mnemonic());
-
- if ((ref($asm) eq 'CODE') && scalar(my @bytes=&$asm($line))) {
- print $gas?".byte\t":"DB\t",join(',',@bytes),"\n";
- next;
- }
-
- my @args;
- ARGUMENT: while (1) {
- my $arg;
-
- ($arg=register->re(\$line, $opcode))||
- ($arg=const->re(\$line)) ||
- ($arg=ea->re(\$line, $opcode)) ||
- ($arg=expr->re(\$line, $opcode)) ||
- last ARGUMENT;
-
- push @args,$arg;
-
- last ARGUMENT if ($line !~ /^,/);
-
- $line =~ s/^,\s*//;
- } # ARGUMENT:
-
- if ($#args>=0) {
- my $insn;
- my $sz=$opcode->size();
-
- if ($gas) {
- $insn = $opcode->out($#args>=1?$args[$#args]->size():$sz);
- @args = map($_->out($sz),@args);
- printf "\t%s\t%s",$insn,join(",",@args);
- } else {
- $insn = $opcode->out();
- foreach (@args) {
- my $arg = $_->out();
- # $insn.=$sz compensates for movq, pinsrw, ...
- if ($arg =~ /^xmm[0-9]+$/) { $insn.=$sz; $sz="x" if(!$sz); last; }
- if ($arg =~ /^ymm[0-9]+$/) { $insn.=$sz; $sz="y" if(!$sz); last; }
- if ($arg =~ /^zmm[0-9]+$/) { $insn.=$sz; $sz="z" if(!$sz); last; }
- if ($arg =~ /^mm[0-9]+$/) { $insn.=$sz; $sz="q" if(!$sz); last; }
- }
- @args = reverse(@args);
- undef $sz if ($nasm && $opcode->mnemonic() eq "lea");
- printf "\t%s\t%s",$insn,join(",",map($_->out($sz),@args));
- }
- } else {
- printf "\t%s",$opcode->out();
- }
- }
-
- print $line,"\n";
-}
-
-print "\n$current_segment\tENDS\n" if ($current_segment && $masm);
-print "END\n" if ($masm);
-
-close STDOUT;
-
-#################################################
-# Cross-reference x86_64 ABI "card"
-#
-# Unix Win64
-# %rax * *
-# %rbx - -
-# %rcx #4 #1
-# %rdx #3 #2
-# %rsi #2 -
-# %rdi #1 -
-# %rbp - -
-# %rsp - -
-# %r8 #5 #3
-# %r9 #6 #4
-# %r10 * *
-# %r11 * *
-# %r12 - -
-# %r13 - -
-# %r14 - -
-# %r15 - -
-#
-# (*) volatile register
-# (-) preserved by callee
-# (#) Nth argument, volatile
-#
-# In Unix terms top of stack is argument transfer area for arguments
-# which could not be accommodated in registers. Or in other words 7th
-# [integer] argument resides at 8(%rsp) upon function entry point.
-# 128 bytes above %rsp constitute a "red zone" which is not touched
-# by signal handlers and can be used as temporal storage without
-# allocating a frame.
-#
-# In Win64 terms N*8 bytes on top of stack is argument transfer area,
-# which belongs to/can be overwritten by callee. N is the number of
-# arguments passed to callee, *but* not less than 4! This means that
-# upon function entry point 5th argument resides at 40(%rsp), as well
-# as that 32 bytes from 8(%rsp) can always be used as temporal
-# storage [without allocating a frame]. One can actually argue that
-# one can assume a "red zone" above stack pointer under Win64 as well.
-# Point is that at apparently no occasion Windows kernel would alter
-# the area above user stack pointer in true asynchronous manner...
-#
-# All the above means that if assembler programmer adheres to Unix
-# register and stack layout, but disregards the "red zone" existence,
-# it's possible to use following prologue and epilogue to "gear" from
-# Unix to Win64 ABI in leaf functions with not more than 6 arguments.
-#
-# omnipotent_function:
-# ifdef WIN64
-# movq %rdi,8(%rsp)
-# movq %rsi,16(%rsp)
-# movq %rcx,%rdi ; if 1st argument is actually present
-# movq %rdx,%rsi ; if 2nd argument is actually ...
-# movq %r8,%rdx ; if 3rd argument is ...
-# movq %r9,%rcx ; if 4th argument ...
-# movq 40(%rsp),%r8 ; if 5th ...
-# movq 48(%rsp),%r9 ; if 6th ...
-# endif
-# ...
-# ifdef WIN64
-# movq 8(%rsp),%rdi
-# movq 16(%rsp),%rsi
-# endif
-# ret
-#
-#################################################
-# Win64 SEH, Structured Exception Handling.
-#
-# Unlike on Unix systems(*) lack of Win64 stack unwinding information
-# has undesired side-effect at run-time: if an exception is raised in
-# assembler subroutine such as those in question (basically we're
-# referring to segmentation violations caused by malformed input
-# parameters), the application is briskly terminated without invoking
-# any exception handlers, most notably without generating memory dump
-# or any user notification whatsoever. This poses a problem. It's
-# possible to address it by registering custom language-specific
-# handler that would restore processor context to the state at
-# subroutine entry point and return "exception is not handled, keep
-# unwinding" code. Writing such handler can be a challenge... But it's
-# doable, though requires certain coding convention. Consider following
-# snippet:
-#
-# .type function,@function
-# function:
-# movq %rsp,%rax # copy rsp to volatile register
-# pushq %r15 # save non-volatile registers
-# pushq %rbx
-# pushq %rbp
-# movq %rsp,%r11
-# subq %rdi,%r11 # prepare [variable] stack frame
-# andq $-64,%r11
-# movq %rax,0(%r11) # check for exceptions
-# movq %r11,%rsp # allocate [variable] stack frame
-# movq %rax,0(%rsp) # save original rsp value
-# magic_point:
-# ...
-# movq 0(%rsp),%rcx # pull original rsp value
-# movq -24(%rcx),%rbp # restore non-volatile registers
-# movq -16(%rcx),%rbx
-# movq -8(%rcx),%r15
-# movq %rcx,%rsp # restore original rsp
-# magic_epilogue:
-# ret
-# .size function,.-function
-#
-# The key is that up to magic_point copy of original rsp value remains
-# in chosen volatile register and no non-volatile register, except for
-# rsp, is modified. While past magic_point rsp remains constant till
-# the very end of the function. In this case custom language-specific
-# exception handler would look like this:
-#
-# EXCEPTION_DISPOSITION handler (EXCEPTION_RECORD *rec,ULONG64 frame,
-# CONTEXT *context,DISPATCHER_CONTEXT *disp)
-# { ULONG64 *rsp = (ULONG64 *)context->Rax;
-# ULONG64 rip = context->Rip;
-#
-# if (rip >= magic_point)
-# { rsp = (ULONG64 *)context->Rsp;
-# if (rip < magic_epilogue)
-# { rsp = (ULONG64 *)rsp[0];
-# context->Rbp = rsp[-3];
-# context->Rbx = rsp[-2];
-# context->R15 = rsp[-1];
-# }
-# }
-# context->Rsp = (ULONG64)rsp;
-# context->Rdi = rsp[1];
-# context->Rsi = rsp[2];
-#
-# memcpy (disp->ContextRecord,context,sizeof(CONTEXT));
-# RtlVirtualUnwind(UNW_FLAG_NHANDLER,disp->ImageBase,
-# dips->ControlPc,disp->FunctionEntry,disp->ContextRecord,
-# &disp->HandlerData,&disp->EstablisherFrame,NULL);
-# return ExceptionContinueSearch;
-# }
-#
-# It's appropriate to implement this handler in assembler, directly in
-# function's module. In order to do that one has to know members'
-# offsets in CONTEXT and DISPATCHER_CONTEXT structures and some constant
-# values. Here they are:
-#
-# CONTEXT.Rax 120
-# CONTEXT.Rcx 128
-# CONTEXT.Rdx 136
-# CONTEXT.Rbx 144
-# CONTEXT.Rsp 152
-# CONTEXT.Rbp 160
-# CONTEXT.Rsi 168
-# CONTEXT.Rdi 176
-# CONTEXT.R8 184
-# CONTEXT.R9 192
-# CONTEXT.R10 200
-# CONTEXT.R11 208
-# CONTEXT.R12 216
-# CONTEXT.R13 224
-# CONTEXT.R14 232
-# CONTEXT.R15 240
-# CONTEXT.Rip 248
-# CONTEXT.Xmm6 512
-# sizeof(CONTEXT) 1232
-# DISPATCHER_CONTEXT.ControlPc 0
-# DISPATCHER_CONTEXT.ImageBase 8
-# DISPATCHER_CONTEXT.FunctionEntry 16
-# DISPATCHER_CONTEXT.EstablisherFrame 24
-# DISPATCHER_CONTEXT.TargetIp 32
-# DISPATCHER_CONTEXT.ContextRecord 40
-# DISPATCHER_CONTEXT.LanguageHandler 48
-# DISPATCHER_CONTEXT.HandlerData 56
-# UNW_FLAG_NHANDLER 0
-# ExceptionContinueSearch 1
-#
-# In order to tie the handler to the function one has to compose
-# couple of structures: one for .xdata segment and one for .pdata.
-#
-# UNWIND_INFO structure for .xdata segment would be
-#
-# function_unwind_info:
-# .byte 9,0,0,0
-# .rva handler
-#
-# This structure designates exception handler for a function with
-# zero-length prologue, no stack frame or frame register.
-#
-# To facilitate composing of .pdata structures, auto-generated "gear"
-# prologue copies rsp value to rax and denotes next instruction with
-# .LSEH_begin_{function_name} label. This essentially defines the SEH
-# styling rule mentioned in the beginning. Position of this label is
-# chosen in such manner that possible exceptions raised in the "gear"
-# prologue would be accounted to caller and unwound from latter's frame.
-# End of function is marked with respective .LSEH_end_{function_name}
-# label. To summarize, .pdata segment would contain
-#
-# .rva .LSEH_begin_function
-# .rva .LSEH_end_function
-# .rva function_unwind_info
-#
-# Reference to function_unwind_info from .xdata segment is the anchor.
-# In case you wonder why references are 32-bit .rvas and not 64-bit
-# .quads. References put into these two segments are required to be
-# *relative* to the base address of the current binary module, a.k.a.
-# image base. No Win64 module, be it .exe or .dll, can be larger than
-# 2GB and thus such relative references can be and are accommodated in
-# 32 bits.
-#
-# Having reviewed the example function code, one can argue that "movq
-# %rsp,%rax" above is redundant. It is not! Keep in mind that on Unix
-# rax would contain an undefined value. If this "offends" you, use
-# another register and refrain from modifying rax till magic_point is
-# reached, i.e. as if it was a non-volatile register. If more registers
-# are required prior [variable] frame setup is completed, note that
-# nobody says that you can have only one "magic point." You can
-# "liberate" non-volatile registers by denoting last stack off-load
-# instruction and reflecting it in finer grade unwind logic in handler.
-# After all, isn't it why it's called *language-specific* handler...
-#
-# SE handlers are also involved in unwinding stack when executable is
-# profiled or debugged. Profiling implies additional limitations that
-# are too subtle to discuss here. For now it's sufficient to say that
-# in order to simplify handlers one should either a) offload original
-# %rsp to stack (like discussed above); or b) if you have a register to
-# spare for frame pointer, choose volatile one.
-#
-# (*) Note that we're talking about run-time, not debug-time. Lack of
-# unwind information makes debugging hard on both Windows and
-# Unix. "Unlike" refers to the fact that on Unix signal handler
-# will always be invoked, core dumped and appropriate exit code
-# returned to parent (for user notification).