diff options
| author | Robert Clausecker <fuz@FreeBSD.org> | 2023-09-11 23:56:30 +0000 |
|---|---|---|
| committer | Robert Clausecker <fuz@FreeBSD.org> | 2023-09-12 02:58:43 +0000 |
| commit | 52d4a4d4e0dedc72bc33082a3f84c2d0fd6f2cbb (patch) | |
| tree | d8cc9182616c717fbd653257cbdd5d1d3a6f90d0 /lib/libc/amd64/string | |
| parent | fafb03ab4254ab0d3927bc8ec22e4ba432efdbeb (diff) | |
Diffstat (limited to 'lib/libc/amd64/string')
| -rw-r--r-- | lib/libc/amd64/string/strcspn.S | 25 |
1 files changed, 15 insertions, 10 deletions
diff --git a/lib/libc/amd64/string/strcspn.S b/lib/libc/amd64/string/strcspn.S index de409db6d472..53100eeea9a5 100644 --- a/lib/libc/amd64/string/strcspn.S +++ b/lib/libc/amd64/string/strcspn.S @@ -259,27 +259,32 @@ ARCHENTRY(strcspn, x86_64_v2) movdqu 48(%rsp, %rcx, 1), %xmm3 # second part of set /* set is 17--32 bytes in size */ - pcmpistri $0, %xmm0, %xmm2 # match in head? - jbe .Lheadmatchv2 - pcmpistri $0, %xmm0, %xmm3 # ZF=1 not possible here + pcmpistri $0, %xmm0, %xmm2 # match in first set half? jb .Lheadmatchv2 + pcmpistri $0, %xmm0, %xmm3 # match in second set half or end of string? + jbe .Lheadmatchv2 ALIGN_TEXT 0: movdqa (%rax), %xmm0 pcmpistri $0, %xmm0, %xmm2 - jbe 1b + jb 2f # match in first set half? pcmpistri $0, %xmm0, %xmm3 - jb 1f # ZF=1 not possible here + jbe 1f # match in second set half or end of string? movdqa 16(%rax), %xmm0 add $32, %rax pcmpistri $0, %xmm0, %xmm2 - jbe 3b + jb 3f # match in first set half? pcmpistri $0, %xmm0, %xmm3 - jae 0b # ZF=1 not possible here + ja 0b # neither match in 2nd half nor string end? - sub $16, %rax # go back to second half -1: add %rcx, %rax - sub %rdi, %rax +3: lea -16(%rax), %rax # go back to second half +1: jc 2f # jump if match found + pxor %xmm1, %xmm1 + pcmpeqb %xmm1, %xmm0 # where is the NUL byte? + pmovmskb %xmm0, %ecx + tzcnt %ecx, %ecx # location of NUL byte in (%rax) +2: sub %rdi, %rax # offset of %xmm0 from beginning of string + add %rcx, %rax # prefix length before match/NUL leave ret |