xref: /aosp_15_r20/external/cronet/third_party/boringssl/src/crypto/fipsmodule/rand/asm/rdrand-x86_64.pl (revision 6777b5387eb2ff775bb5750e3f5d96f37fb7352b)
1#!/usr/bin/env perl
2
3# Copyright (c) 2015, Google Inc.
4#
5# Permission to use, copy, modify, and/or distribute this software for any
6# purpose with or without fee is hereby granted, provided that the above
7# copyright notice and this permission notice appear in all copies.
8#
9# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
12# SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
14# OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
15# CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
16
17use strict;
18
19my $flavour = shift;
20my $output  = shift;
21if ($flavour =~ /\./) { $output = $flavour; undef $flavour; }
22
23my $win64 = 0;
24$win64 = 1 if ($flavour =~ /[nm]asm|mingw64/ || $output =~ /\.asm$/);
25
26$0 =~ m/(.*[\/\\])[^\/\\]+$/;
27my $dir = $1;
28my $xlate;
29( $xlate="${dir}../../../perlasm/x86_64-xlate.pl" and -f $xlate) or
30die "can't locate x86_64-xlate.pl";
31
32open OUT,"| \"$^X\" \"$xlate\" $flavour \"$output\"";
33*STDOUT=*OUT;
34
35my ($out, $len, $tmp1, $tmp2) = $win64 ? ("%rcx", "%rdx", "%r8", "%r9")
36                                       : ("%rdi", "%rsi", "%rdx", "%rcx");
37
38print<<___;
39.text
40
41# CRYPTO_rdrand writes eight bytes of random data from the hardware RNG to
42# |out|. It returns one on success or zero on hardware failure.
43# int CRYPTO_rdrand(uint8_t out[8]);
44.globl	CRYPTO_rdrand
45.type	CRYPTO_rdrand,\@abi-omnipotent
46.align	16
47CRYPTO_rdrand:
48.cfi_startproc
49	_CET_ENDBR
50	xorq %rax, %rax
51	rdrand $tmp1
52	# An add-with-carry of zero effectively sets %rax to the carry flag.
53	adcq %rax, %rax
54	movq $tmp1, 0($out)
55	retq
56.cfi_endproc
57.size CRYPTO_rdrand,.-CRYPTO_rdrand
58
59# CRYPTO_rdrand_multiple8_buf fills |len| bytes at |buf| with random data from
60# the hardware RNG. The |len| argument must be a multiple of eight. It returns
61# one on success and zero on hardware failure.
62# int CRYPTO_rdrand_multiple8_buf(uint8_t *buf, size_t len);
63.globl CRYPTO_rdrand_multiple8_buf
64.type CRYPTO_rdrand_multiple8_buf,\@abi-omnipotent
65.align 16
66CRYPTO_rdrand_multiple8_buf:
67.cfi_startproc
68	_CET_ENDBR
69	test $len, $len
70	jz .Lout
71	movq \$8, $tmp1
72.Lloop:
73	rdrand $tmp2
74	jnc .Lerr
75	movq $tmp2, 0($out)
76	addq $tmp1, $out
77	subq $tmp1, $len
78	jnz .Lloop
79.Lout:
80	movq \$1, %rax
81	retq
82.Lerr:
83	xorq %rax, %rax
84	retq
85.cfi_endproc
86.size CRYPTO_rdrand_multiple8_buf,.-CRYPTO_rdrand_multiple8_buf
87___
88
89close STDOUT or die "error closing STDOUT: $!";	# flush
90