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crypto: x86/aes-gcm - code size optimization

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Prefer immediates of -128 to 128, since the former fits in a signed
byte, saving 3 bytes per instruction.  Also replace a vpand and vpxor
with a vpternlogd.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Eric Biggers
2024-12-12 13:28:38 -08:00
committed by Herbert Xu
parent b9b894642f
commit 3cae5a3c05
1 changed files with 10 additions and 10 deletions
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20
arch/x86/crypto/aes-gcm-avx10-x86_64.S
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@@ -384,8 +384,8 @@
vpshufd $0xd3, H_CUR_XMM, %xmm0
vpsrad $31, %xmm0, %xmm0
vpaddq H_CUR_XMM, H_CUR_XMM, H_CUR_XMM
vpand .Lgfpoly_and_internal_carrybit(%rip), %xmm0, %xmm0
vpxor %xmm0, H_CUR_XMM, H_CUR_XMM
// H_CUR_XMM ^= xmm0 & gfpoly_and_internal_carrybit
vpternlogd $0x78, .Lgfpoly_and_internal_carrybit(%rip), %xmm0, H_CUR_XMM
// Load the gfpoly constant.
vbroadcasti32x4 .Lgfpoly(%rip), GFPOLY
@@ -713,7 +713,7 @@
// Pre-subtracting 4*VL from DATALEN saves an instruction from the main
// loop and also ensures that at least one write always occurs to
// DATALEN, zero-extending it and allowing DATALEN64 to be used later.
sub $4*VL, DATALEN
add $-4*VL, DATALEN // shorter than 'sub 4*VL' when VL=32
jl .Lcrypt_loop_4x_done\@
// Load powers of the hash key.
@@ -760,9 +760,9 @@
vmovdqu8 GHASHDATA1, 1*VL(DST)
vmovdqu8 GHASHDATA2, 2*VL(DST)
vmovdqu8 GHASHDATA3, 3*VL(DST)
add $4*VL, SRC
add $4*VL, DST
sub $4*VL, DATALEN
sub $-4*VL, SRC // shorter than 'add 4*VL' when VL=32
sub $-4*VL, DST
add $-4*VL, DATALEN
jl .Lghash_last_ciphertext_4x\@
.endif
@@ -840,9 +840,9 @@
vmovdqu8 GHASHDATA2, 2*VL(DST)
vmovdqu8 GHASHDATA3, 3*VL(DST)
add $4*VL, SRC
add $4*VL, DST
sub $4*VL, DATALEN
sub $-4*VL, SRC // shorter than 'add 4*VL' when VL=32
sub $-4*VL, DST
add $-4*VL, DATALEN
jge .Lcrypt_loop_4x\@
.if \enc
@@ -856,7 +856,7 @@
.Lcrypt_loop_4x_done\@:
// Undo the extra subtraction by 4*VL and check whether data remains.
add $4*VL, DATALEN
sub $-4*VL, DATALEN // shorter than 'add 4*VL' when VL=32
jz .Ldone\@
// The data length isn't a multiple of 4*VL. Process the remaining data