busybox/libbb/hash_md5_sha_x86-64.S.sh
Denys Vlasenko 4923f74e58 libbb/sha1: shrink unrolled x86-64 code
function                                             old     new   delta
sha1_process_block64                                3482    3481      -1
.rodata                                           108460  108412     -48
------------------------------------------------------------------------------
(add/remove: 1/4 grow/shrink: 0/2 up/down: 0/-49)             Total: -49 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2022-02-08 03:29:16 +01:00

452 lines
14 KiB
Bash
Executable File

#!/bin/sh
# We don't regenerate it on every "make" invocation - only by hand.
# The reason is that the changes to generated code are difficult
# to visualize by looking only at this script, it helps when the commit
# also contains the diff of the generated file.
exec >hash_md5_sha_x86-64.S
# Based on http://arctic.org/~dean/crypto/sha1.html.
# ("This SHA1 implementation is public domain.")
#
# x86-64 has at least SSE2 vector insns always available.
# We can use them without any CPUID checks (and without a need
# for a fallback code if needed insns are not available).
# This code uses them to calculate W[] ahead of time.
#
# Unfortunately, results are passed from vector unit to
# integer ALUs on the stack. MOVD/Q insns to move them directly
# from vector to integer registers are slower than store-to-load
# forwarding in LSU (on Skylake at least).
#
# The win against a purely integer code is small on Skylake,
# only about 7-8%. We offload about 1/3 of our operations to the vector unit.
# It can do 4 ops at once in one 128-bit register,
# but we have to use x2 of them because of W[0] complication,
# SSE2 has no "rotate each word by N bits" insns,
# moving data to/from vector unit is clunky, and Skylake
# has four integer ALUs unified with three vector ALUs,
# which makes pure integer code rather fast, and makes
# vector ops compete with integer ones.
#
# Zen3, with its separate vector ALUs, wins more, about 12%.
xmmT1="%xmm4"
xmmT2="%xmm5"
xmmRCONST="%xmm6"
xmmALLRCONST="%xmm7"
T=`printf '\t'`
# SSE instructions are longer than 4 bytes on average.
# Intel CPUs (up to Tiger Lake at least) can't decode
# more than 16 bytes of code in one cycle.
# By interleaving SSE code and integer code
# we mostly achieve a situation where 16-byte decode fetch window
# contains 4 (or more) insns.
#
# However. On Skylake, there was no observed difference,
# but on Zen3, non-interleaved code is ~3% faster
# (822 Mb/s versus 795 Mb/s hashing speed).
# Off for now:
interleave=false
INTERLEAVE() {
$interleave || \
{
# Generate non-interleaved code
# (it should work correctly too)
echo "$1"
echo "$2"
return
}
(
echo "$1" | grep -v '^$' >"$0.temp1"
echo "$2" | grep -v '^$' >"$0.temp2"
exec 3<"$0.temp1"
exec 4<"$0.temp2"
IFS=''
while :; do
line1=''
line2=''
while :; do
read -r line1 <&3
if test "${line1:0:1}" != "#" && test "${line1:0:2}" != "$T#"; then
break
fi
echo "$line1"
done
while :; do
read -r line2 <&4
if test "${line2:0:4}" = "${T}lea"; then
# We use 7-8 byte long forms of LEA.
# Do not interleave them with SSE insns
# which are also long.
echo "$line2"
read -r line2 <&4
echo "$line2"
continue
fi
if test "${line2:0:1}" != "#" && test "${line2:0:2}" != "$T#"; then
break
fi
echo "$line2"
done
test "$line1$line2" || break
echo "$line1"
echo "$line2"
done
rm "$0.temp1" "$0.temp2"
)
}
echo \
"### Generated by hash_md5_sha_x86-64.S.sh ###
#if CONFIG_SHA1_SMALL == 0 && defined(__GNUC__) && defined(__x86_64__)
.section .text.sha1_process_block64, \"ax\", @progbits
.globl sha1_process_block64
.hidden sha1_process_block64
.type sha1_process_block64, @function
.balign 8 # allow decoders to fetch at least 5 first insns
sha1_process_block64:
pushq %rbp # 1 byte insn
pushq %rbx # 1 byte insn
# pushq %r15 # 2 byte insn
pushq %r14 # 2 byte insn
pushq %r13 # 2 byte insn
pushq %r12 # 2 byte insn
pushq %rdi # we need ctx at the end
#Register and stack use:
# eax..edx: a..d
# ebp: e
# esi,edi,r8..r14: temps
# r15: unused
# xmm0..xmm3: W[]
# xmm4,xmm5: temps
# xmm6: current round constant
# xmm7: all round constants
# -64(%rsp): area for passing RCONST + W[] from vector to integer units
movl 80(%rdi), %eax # a = ctx->hash[0]
movl 84(%rdi), %ebx # b = ctx->hash[1]
movl 88(%rdi), %ecx # c = ctx->hash[2]
movl 92(%rdi), %edx # d = ctx->hash[3]
movl 96(%rdi), %ebp # e = ctx->hash[4]
movaps sha1const(%rip), $xmmALLRCONST
pshufd \$0x00, $xmmALLRCONST, $xmmRCONST
# Load W[] to xmm registers, byteswapping on the fly.
#
# For iterations 0..15, we pass W[] in rsi,r8..r14
# for use in RD1As instead of spilling them to stack.
# We lose parallelized addition of RCONST, but LEA
# can do two additions at once, so it is probably a wash.
# (We use rsi instead of rN because this makes two
# LEAs in two first RD1As shorter by one byte).
movq 4*0(%rdi), %rsi
movq 4*2(%rdi), %r8
bswapq %rsi
bswapq %r8
rolq \$32, %rsi # rsi = W[1]:W[0]
rolq \$32, %r8 # r8 = W[3]:W[2]
movq %rsi, %xmm0
movq %r8, $xmmT1
punpcklqdq $xmmT1, %xmm0 # xmm0 = r8:rsi = (W[0],W[1],W[2],W[3])
# movaps %xmm0, $xmmT1 # add RCONST, spill to stack
# paddd $xmmRCONST, $xmmT1
# movups $xmmT1, -64+16*0(%rsp)
movq 4*4(%rdi), %r9
movq 4*6(%rdi), %r10
bswapq %r9
bswapq %r10
rolq \$32, %r9 # r9 = W[5]:W[4]
rolq \$32, %r10 # r10 = W[7]:W[6]
movq %r9, %xmm1
movq %r10, $xmmT1
punpcklqdq $xmmT1, %xmm1 # xmm1 = r10:r9 = (W[4],W[5],W[6],W[7])
movq 4*8(%rdi), %r11
movq 4*10(%rdi), %r12
bswapq %r11
bswapq %r12
rolq \$32, %r11 # r11 = W[9]:W[8]
rolq \$32, %r12 # r12 = W[11]:W[10]
movq %r11, %xmm2
movq %r12, $xmmT1
punpcklqdq $xmmT1, %xmm2 # xmm2 = r12:r11 = (W[8],W[9],W[10],W[11])
movq 4*12(%rdi), %r13
movq 4*14(%rdi), %r14
bswapq %r13
bswapq %r14
rolq \$32, %r13 # r13 = W[13]:W[12]
rolq \$32, %r14 # r14 = W[15]:W[14]
movq %r13, %xmm3
movq %r14, $xmmT1
punpcklqdq $xmmT1, %xmm3 # xmm3 = r14:r13 = (W[12],W[13],W[14],W[15])
"
PREP() {
local xmmW0=$1
local xmmW4=$2
local xmmW8=$3
local xmmW12=$4
# the above must be %xmm0..3 in some permutation
local dstmem=$5
#W[0] = rol(W[13] ^ W[8] ^ W[2] ^ W[0], 1);
#W[1] = rol(W[14] ^ W[9] ^ W[3] ^ W[1], 1);
#W[2] = rol(W[15] ^ W[10] ^ W[4] ^ W[2], 1);
#W[3] = rol( 0 ^ W[11] ^ W[5] ^ W[3], 1);
#W[3] ^= rol(W[0], 1);
echo "# PREP $@
movaps $xmmW12, $xmmT1
psrldq \$4, $xmmT1 # rshift by 4 bytes: T1 = ([13],[14],[15],0)
# pshufd \$0x4e, $xmmW0, $xmmT2 # 01001110=2,3,0,1 shuffle, ([2],[3],x,x)
# punpcklqdq $xmmW4, $xmmT2 # T2 = W4[0..63]:T2[0..63] = ([2],[3],[4],[5])
# same result as above, but shorter and faster:
# pshufd/shufps are subtly different: pshufd takes all dwords from source operand,
# shufps takes dwords 0,1 from *2nd* operand, and dwords 2,3 from 1st one!
movaps $xmmW0, $xmmT2
shufps \$0x4e, $xmmW4, $xmmT2 # 01001110=(T2.dw[2], T2.dw[3], W4.dw[0], W4.dw[1]) = ([2],[3],[4],[5])
xorps $xmmW8, $xmmW0 # ([8],[9],[10],[11]) ^ ([0],[1],[2],[3])
xorps $xmmT1, $xmmT2 # ([13],[14],[15],0) ^ ([2],[3],[4],[5])
xorps $xmmT2, $xmmW0 # ^
# W0 = unrotated (W[0]..W[3]), still needs W[3] fixup
movaps $xmmW0, $xmmT2
xorps $xmmT1, $xmmT1 # rol(W0,1):
pcmpgtd $xmmW0, $xmmT1 # ffffffff for elements <0 (ones with msb bit 1)
paddd $xmmW0, $xmmW0 # shift left by 1
psubd $xmmT1, $xmmW0 # add 1 to those who had msb bit 1
# W0 = rotated (W[0]..W[3]), still needs W[3] fixup
pslldq \$12, $xmmT2 # lshift by 12 bytes: T2 = (0,0,0,unrotW[0])
movaps $xmmT2, $xmmT1
pslld \$2, $xmmT2
psrld \$30, $xmmT1
# xorps $xmmT1, $xmmT2 # rol((0,0,0,unrotW[0]),2)
xorps $xmmT1, $xmmW0 # same result, but does not depend on/does not modify T2
xorps $xmmT2, $xmmW0 # W0 = rol(W[0]..W[3],1) ^ (0,0,0,rol(unrotW[0],2))
"
# movq $xmmW0, %r8 # high latency (~6 cycles)
# movaps $xmmW0, $xmmT1
# psrldq \$8, $xmmT1 # rshift by 8 bytes: move upper 64 bits to lower
# movq $xmmT1, %r10 # high latency
# movq %r8, %r9
# movq %r10, %r11
# shrq \$32, %r9
# shrq \$32, %r11
# ^^^ slower than passing the results on stack (!!!)
echo "
movaps $xmmW0, $xmmT2
paddd $xmmRCONST, $xmmT2
movups $xmmT2, $dstmem
"
}
# It's possible to interleave integer insns in rounds to mostly eliminate
# dependency chains, but this likely to only help old Pentium-based
# CPUs (ones without OOO, which can only simultaneously execute a pair
# of _adjacent_ insns).
# Testing on old-ish Silvermont CPU (which has OOO window of only
# about ~8 insns) shows very small (~1%) speedup.
RD1A() {
local a=$1;local b=$2;local c=$3;local d=$4;local e=$5
local n=$(($6))
local n0=$(((n+0) & 15))
local rN=$((7+n0/2))
echo "
# $n
";test $n0 = 0 && echo "
leal $RCONST(%r$e,%rsi), %e$e # e += RCONST + W[n]
shrq \$32, %rsi
";test $n0 = 1 && echo "
leal $RCONST(%r$e,%rsi), %e$e # e += RCONST + W[n]
";test $n0 -ge 2 && test $((n0 & 1)) = 0 && echo "
leal $RCONST(%r$e,%r$rN), %e$e # e += RCONST + W[n]
shrq \$32, %r$rN
";test $n0 -ge 2 && test $((n0 & 1)) = 1 && echo "
leal $RCONST(%r$e,%r$rN), %e$e # e += RCONST + W[n]
";echo "
movl %e$c, %edi # c
xorl %e$d, %edi # ^d
andl %e$b, %edi # &b
xorl %e$d, %edi # (((c ^ d) & b) ^ d)
addl %edi, %e$e # e += (((c ^ d) & b) ^ d)
movl %e$a, %edi #
roll \$5, %edi # rotl32(a,5)
addl %edi, %e$e # e += rotl32(a,5)
rorl \$2, %e$b # b = rotl32(b,30)
"
}
RD1B() {
local a=$1;local b=$2;local c=$3;local d=$4;local e=$5
local n=$(($6))
local n13=$(((n+13) & 15))
local n8=$(((n+8) & 15))
local n2=$(((n+2) & 15))
local n0=$(((n+0) & 15))
echo "
# $n
movl %e$c, %edi # c
xorl %e$d, %edi # ^d
andl %e$b, %edi # &b
xorl %e$d, %edi # (((c ^ d) & b) ^ d)
addl -64+4*$n0(%rsp), %e$e # e += RCONST + W[n & 15]
addl %edi, %e$e # e += (((c ^ d) & b) ^ d)
movl %e$a, %esi #
roll \$5, %esi # rotl32(a,5)
addl %esi, %e$e # e += rotl32(a,5)
rorl \$2, %e$b # b = rotl32(b,30)
"
}
RD2() {
local a=$1;local b=$2;local c=$3;local d=$4;local e=$5
local n=$(($6))
local n13=$(((n+13) & 15))
local n8=$(((n+8) & 15))
local n2=$(((n+2) & 15))
local n0=$(((n+0) & 15))
echo "
# $n
movl %e$c, %edi # c
xorl %e$d, %edi # ^d
xorl %e$b, %edi # ^b
addl -64+4*$n0(%rsp), %e$e # e += RCONST + W[n & 15]
addl %edi, %e$e # e += (c ^ d ^ b)
movl %e$a, %esi #
roll \$5, %esi # rotl32(a,5)
addl %esi, %e$e # e += rotl32(a,5)
rorl \$2, %e$b # b = rotl32(b,30)
"
}
RD3() {
local a=$1;local b=$2;local c=$3;local d=$4;local e=$5
local n=$(($6))
local n13=$(((n+13) & 15))
local n8=$(((n+8) & 15))
local n2=$(((n+2) & 15))
local n0=$(((n+0) & 15))
echo "
# $n
movl %e$b, %edi # di: b
movl %e$b, %esi # si: b
orl %e$c, %edi # di: b | c
andl %e$c, %esi # si: b & c
andl %e$d, %edi # di: (b | c) & d
orl %esi, %edi # ((b | c) & d) | (b & c)
addl %edi, %e$e # += ((b | c) & d) | (b & c)
addl -64+4*$n0(%rsp), %e$e # e += RCONST + W[n & 15]
movl %e$a, %esi #
roll \$5, %esi # rotl32(a,5)
addl %esi, %e$e # e += rotl32(a,5)
rorl \$2, %e$b # b = rotl32(b,30)
"
}
{
# Round 1
RCONST=0x5A827999
RD1A ax bx cx dx bp 0; RD1A bp ax bx cx dx 1; RD1A dx bp ax bx cx 2; RD1A cx dx bp ax bx 3;
RD1A bx cx dx bp ax 4; RD1A ax bx cx dx bp 5; RD1A bp ax bx cx dx 6; RD1A dx bp ax bx cx 7;
a=`PREP %xmm0 %xmm1 %xmm2 %xmm3 "-64+16*0(%rsp)"`
b=`RD1A cx dx bp ax bx 8; RD1A bx cx dx bp ax 9; RD1A ax bx cx dx bp 10; RD1A bp ax bx cx dx 11;`
INTERLEAVE "$a" "$b"
a=`echo " pshufd \\$0x55, $xmmALLRCONST, $xmmRCONST"
PREP %xmm1 %xmm2 %xmm3 %xmm0 "-64+16*1(%rsp)"`
b=`RD1A dx bp ax bx cx 12; RD1A cx dx bp ax bx 13; RD1A bx cx dx bp ax 14; RD1A ax bx cx dx bp 15;`
INTERLEAVE "$a" "$b"
a=`PREP %xmm2 %xmm3 %xmm0 %xmm1 "-64+16*2(%rsp)"`
b=`RD1B bp ax bx cx dx 16; RD1B dx bp ax bx cx 17; RD1B cx dx bp ax bx 18; RD1B bx cx dx bp ax 19;`
INTERLEAVE "$a" "$b"
# Round 2
RCONST=0x6ED9EBA1
a=`PREP %xmm3 %xmm0 %xmm1 %xmm2 "-64+16*3(%rsp)"`
b=`RD2 ax bx cx dx bp 20; RD2 bp ax bx cx dx 21; RD2 dx bp ax bx cx 22; RD2 cx dx bp ax bx 23;`
INTERLEAVE "$a" "$b"
a=`PREP %xmm0 %xmm1 %xmm2 %xmm3 "-64+16*0(%rsp)"`
b=`RD2 bx cx dx bp ax 24; RD2 ax bx cx dx bp 25; RD2 bp ax bx cx dx 26; RD2 dx bp ax bx cx 27;`
INTERLEAVE "$a" "$b"
a=`PREP %xmm1 %xmm2 %xmm3 %xmm0 "-64+16*1(%rsp)"`
b=`RD2 cx dx bp ax bx 28; RD2 bx cx dx bp ax 29; RD2 ax bx cx dx bp 30; RD2 bp ax bx cx dx 31;`
INTERLEAVE "$a" "$b"
a=`echo " pshufd \\$0xaa, $xmmALLRCONST, $xmmRCONST"
PREP %xmm2 %xmm3 %xmm0 %xmm1 "-64+16*2(%rsp)"`
b=`RD2 dx bp ax bx cx 32; RD2 cx dx bp ax bx 33; RD2 bx cx dx bp ax 34; RD2 ax bx cx dx bp 35;`
INTERLEAVE "$a" "$b"
a=`PREP %xmm3 %xmm0 %xmm1 %xmm2 "-64+16*3(%rsp)"`
b=`RD2 bp ax bx cx dx 36; RD2 dx bp ax bx cx 37; RD2 cx dx bp ax bx 38; RD2 bx cx dx bp ax 39;`
INTERLEAVE "$a" "$b"
# Round 3
RCONST=0x8F1BBCDC
a=`PREP %xmm0 %xmm1 %xmm2 %xmm3 "-64+16*0(%rsp)"`
b=`RD3 ax bx cx dx bp 40; RD3 bp ax bx cx dx 41; RD3 dx bp ax bx cx 42; RD3 cx dx bp ax bx 43;`
INTERLEAVE "$a" "$b"
a=`PREP %xmm1 %xmm2 %xmm3 %xmm0 "-64+16*1(%rsp)"`
b=`RD3 bx cx dx bp ax 44; RD3 ax bx cx dx bp 45; RD3 bp ax bx cx dx 46; RD3 dx bp ax bx cx 47;`
INTERLEAVE "$a" "$b"
a=`PREP %xmm2 %xmm3 %xmm0 %xmm1 "-64+16*2(%rsp)"`
b=`RD3 cx dx bp ax bx 48; RD3 bx cx dx bp ax 49; RD3 ax bx cx dx bp 50; RD3 bp ax bx cx dx 51;`
INTERLEAVE "$a" "$b"
a=`echo " pshufd \\$0xff, $xmmALLRCONST, $xmmRCONST"
PREP %xmm3 %xmm0 %xmm1 %xmm2 "-64+16*3(%rsp)"`
b=`RD3 dx bp ax bx cx 52; RD3 cx dx bp ax bx 53; RD3 bx cx dx bp ax 54; RD3 ax bx cx dx bp 55;`
INTERLEAVE "$a" "$b"
a=`PREP %xmm0 %xmm1 %xmm2 %xmm3 "-64+16*0(%rsp)"`
b=`RD3 bp ax bx cx dx 56; RD3 dx bp ax bx cx 57; RD3 cx dx bp ax bx 58; RD3 bx cx dx bp ax 59;`
INTERLEAVE "$a" "$b"
# Round 4 has the same logic as round 2, only n and RCONST are different
RCONST=0xCA62C1D6
a=`PREP %xmm1 %xmm2 %xmm3 %xmm0 "-64+16*1(%rsp)"`
b=`RD2 ax bx cx dx bp 60; RD2 bp ax bx cx dx 61; RD2 dx bp ax bx cx 62; RD2 cx dx bp ax bx 63;`
INTERLEAVE "$a" "$b"
a=`PREP %xmm2 %xmm3 %xmm0 %xmm1 "-64+16*2(%rsp)"`
b=`RD2 bx cx dx bp ax 64; RD2 ax bx cx dx bp 65; RD2 bp ax bx cx dx 66; RD2 dx bp ax bx cx 67;`
INTERLEAVE "$a" "$b"
a=`PREP %xmm3 %xmm0 %xmm1 %xmm2 "-64+16*3(%rsp)"`
b=`RD2 cx dx bp ax bx 68; RD2 bx cx dx bp ax 69; RD2 ax bx cx dx bp 70; RD2 bp ax bx cx dx 71;`
INTERLEAVE "$a" "$b"
RD2 dx bp ax bx cx 72; RD2 cx dx bp ax bx 73; RD2 bx cx dx bp ax 74; RD2 ax bx cx dx bp 75;
RD2 bp ax bx cx dx 76; RD2 dx bp ax bx cx 77; RD2 cx dx bp ax bx 78; RD2 bx cx dx bp ax 79;
} | grep -v '^$'
echo "
popq %rdi #
popq %r12 #
addl %eax, 80(%rdi) # ctx->hash[0] += a
popq %r13 #
addl %ebx, 84(%rdi) # ctx->hash[1] += b
popq %r14 #
addl %ecx, 88(%rdi) # ctx->hash[2] += c
# popq %r15 #
addl %edx, 92(%rdi) # ctx->hash[3] += d
popq %rbx #
addl %ebp, 96(%rdi) # ctx->hash[4] += e
popq %rbp #
ret
.size sha1_process_block64, .-sha1_process_block64
.section .rodata.cst16.sha1const, \"aM\", @progbits, 16
.balign 16
sha1const:
.long 0x5A827999
.long 0x6ED9EBA1
.long 0x8F1BBCDC
.long 0xCA62C1D6
#endif"