libbb/sha1: shrink unrolled x86-64 code

function                                             old     new   delta
sha1_process_block64                                3481    3384     -97

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 54 insertions, 57 deletions

diff --git a/libbb/hash_md5_sha_x86-64.S.sh b/libbb/hash_md5_sha_x86-64.S.sh
index a10ac411d..f34e6e6fa 100755
--- a/libbb/hash_md5_sha_x86-64.S.sh
+++ b/libbb/hash_md5_sha_x86-64.S.sh
@@ -129,65 +129,57 @@ sha1_process_block64:
 # 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
+        movaps  bswap32_mask(%rip), $xmmT1
         pshufd  \$0x00, $xmmALLRCONST, $xmmRCONST
 
-        # Load W[] to xmm registers, byteswapping on the fly.
+        # Load W[] to xmm0..3, byteswapping on the fly.
         #
-        # For iterations 0..15, we pass W[] in rsi,r8..r14
+        # For iterations 0..15, we pass RCONST+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])
+        # ADDs in two first RD1As shorter by one byte).
+        movups  16*0(%rdi), %xmm0
+        pshufb  $xmmT1, %xmm0
+        movaps  %xmm0, $xmmT2
+        paddd   $xmmRCONST, $xmmT2
+        movq    $xmmT2, %rsi
+#       pextrq  \$1, $xmmT2, %r8        #SSE4.1 insn
+#       movhpd  $xmmT2, %r8             #can only move to mem, not to reg
+        shufps  \$0x0e, $xmmT2, $xmmT2
+        movq    $xmmT2, %r8
+
+        movups  16*1(%rdi), %xmm1
+        pshufb  $xmmT1, %xmm1
+        movaps  %xmm1, $xmmT2
+        paddd   $xmmRCONST, $xmmT2
+        movq    $xmmT2, %r9
+        shufps  \$0x0e, $xmmT2, $xmmT2
+        movq    $xmmT2, %r10
+
+        movups  16*2(%rdi), %xmm2
+        pshufb  $xmmT1, %xmm2
+        movaps  %xmm2, $xmmT2
+        paddd   $xmmRCONST, $xmmT2
+        movq    $xmmT2, %r11
+        shufps  \$0x0e, $xmmT2, $xmmT2
+        movq    $xmmT2, %r12
+
+        movups  16*3(%rdi), %xmm3
+        pshufb  $xmmT1, %xmm3
+        movaps  %xmm3, $xmmT2
+        paddd   $xmmRCONST, $xmmT2
+        movq    $xmmT2, %r13
+        shufps  \$0x0e, $xmmT2, $xmmT2
+        movq    $xmmT2, %r14
+
+        # MOVQs to GPRs (above) have somewhat high latency.
+        # Load hash[] while they are completing:
+        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]
 "
 
 PREP() {
@@ -266,15 +258,15 @@ local rN=$((7+n0/2))
 echo "
 # $n
 ";test $n0 = 0 && echo "
-        leal    $RCONST(%r$e,%rsi), %e$e # e += RCONST + W[n]
+        addl    %esi, %e$e              # e += RCONST + W[n]
         shrq    \$32, %rsi
 ";test $n0 = 1 && echo "
-        leal    $RCONST(%r$e,%rsi), %e$e # e += RCONST + W[n]
+        addl    %esi, %e$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]
+        addl    %r${rN}d, %e$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]
+        addl    %r${rN}d, %e$e          # e += RCONST + W[n]
 ";echo "
         movl    %e$c, %edi              # c
         xorl    %e$d, %edi              # ^d
@@ -440,6 +432,11 @@ echo "
         ret
         .size   sha1_process_block64, .-sha1_process_block64
 
+        .section        .rodata.cst16.bswap32_mask, \"aM\", @progbits, 16
+        .balign 16
+bswap32_mask:
+        .octa   0x0c0d0e0f08090a0b0405060700010203
+
         .section        .rodata.cst16.sha1const, \"aM\", @progbits, 16
         .balign 16
 sha1const: