From 4846152a081cb3f0643287dab84c5e2778d9b54e Mon Sep 17 00:00:00 2001 From: Mateusz Guzik Date: Wed, 29 Jan 2020 01:57:07 +0000 Subject: [PATCH] amd64: sync up libc memcmp with the kernel version (r357208) --- lib/libc/amd64/string/memcmp.S | 238 +++++++++++++++++++++++---------- 1 file changed, 166 insertions(+), 72 deletions(-) diff --git a/lib/libc/amd64/string/memcmp.S b/lib/libc/amd64/string/memcmp.S index 3012ffa688c..b8cd3d3df55 100644 --- a/lib/libc/amd64/string/memcmp.S +++ b/lib/libc/amd64/string/memcmp.S @@ -31,91 +31,185 @@ #include __FBSDID("$FreeBSD$"); +#define ALIGN_TEXT .p2align 4,0x90 /* 16-byte alignment, nop filled */ + ENTRY(memcmp) - cmpq $16,%rdx - jae 5f -1: - testq %rdx,%rdx - je 3f - xorl %ecx,%ecx -2: - movzbl (%rdi,%rcx,1),%eax - movzbl (%rsi,%rcx,1),%r8d - cmpb %r8b,%al - jne 4f - addq $1,%rcx - cmpq %rcx,%rdx - jz 3f - movzbl (%rdi,%rcx,1),%eax - movzbl (%rsi,%rcx,1),%r8d - cmpb %r8b,%al - jne 4f - addq $1,%rcx - cmpq %rcx,%rdx - jz 3f - movzbl (%rdi,%rcx,1),%eax - movzbl (%rsi,%rcx,1),%r8d - cmpb %r8b,%al - jne 4f - addq $1,%rcx - cmpq %rcx,%rdx - jz 3f - movzbl (%rdi,%rcx,1),%eax - movzbl (%rsi,%rcx,1),%r8d - cmpb %r8b,%al - jne 4f - addq $1,%rcx - cmpq %rcx,%rdx - jne 2b -3: xorl %eax,%eax - ret -4: - subl %r8d,%eax - ret -5: - cmpq $32,%rdx - jae 7f -6: - /* - * 8 bytes - */ +10: + cmpq $16,%rdx + ja 101632f + +100816: + cmpb $8,%dl + jl 100408f movq (%rdi),%r8 movq (%rsi),%r9 cmpq %r8,%r9 - jne 1b - leaq 8(%rdi),%rdi - leaq 8(%rsi),%rsi - subq $8,%rdx - cmpq $8,%rdx - jae 6b - jl 1b - jmp 3b -7: - /* - * 32 bytes - */ - movq (%rsi),%r8 + jne 1f + movq -8(%rdi,%rdx),%r8 + movq -8(%rsi,%rdx),%r9 + cmpq %r8,%r9 + jne 10081608f + ret +100408: + cmpb $4,%dl + jl 100204f + movl (%rsi),%r8d + movl (%rdi),%r9d + cmpl %r8d,%r9d + jne 1f + movl -4(%rsi,%rdx),%r8d + movl -4(%rdi,%rdx),%r9d + cmpl %r8d,%r9d + jne 1f + ret +100204: + cmpb $2,%dl + jl 100001f + movzwl (%rsi),%r8d + movzwl (%rdi),%r9d + cmpl %r8d,%r9d + jne 1f + movzwl -2(%rsi,%rdx),%r8d + movzwl -2(%rdi,%rdx),%r9d + cmpl %r8d,%r9d + jne 1f + ret +100001: + cmpb $1,%dl + jl 100000f + movzbl (%rdi),%r8d + movzbl (%rsi),%r9d + cmpb %r8b,%r9b + jne 1f +100000: + ret +ALIGN_TEXT +101632: + cmpq $32,%rdx + ja 103200f + movq (%rdi),%r8 + movq (%rsi),%r9 + cmpq %r8,%r9 + jne 1f + movq 8(%rdi),%r8 movq 8(%rsi),%r9 - subq (%rdi),%r8 - subq 8(%rdi),%r9 + cmpq %r8,%r9 + jne 10163208f + movq -16(%rdi,%rdx),%r8 + movq -16(%rsi,%rdx),%r9 + cmpq %r8,%r9 + jne 10163216f + movq -8(%rdi,%rdx),%r8 + movq -8(%rsi,%rdx),%r9 + cmpq %r8,%r9 + jne 10163224f + ret +ALIGN_TEXT +103200: + movq (%rdi),%r8 + movq 8(%rdi),%r9 + subq (%rsi),%r8 + subq 8(%rsi),%r9 or %r8,%r9 - jnz 1b + jnz 10320000f - movq 16(%rsi),%r8 - movq 24(%rsi),%r9 - subq 16(%rdi),%r8 - subq 24(%rdi),%r9 - or %r8,%r9 - jnz 1b + movq 16(%rdi),%r8 + movq 24(%rdi),%r9 + subq 16(%rsi),%r8 + subq 24(%rsi),%r9 + or %r8,%r9 + jnz 10320016f leaq 32(%rdi),%rdi leaq 32(%rsi),%rsi subq $32,%rdx cmpq $32,%rdx - jae 7b - jnz 1b - jmp 3b + jae 103200b + cmpb $0,%dl + jne 10b + ret + +10320016: + leaq 16(%rdi),%rdi + leaq 16(%rsi),%rsi +10320000: +/* + * Mismatch was found within a 16 bytes range. The part of the routine + * which calculates it only operates on sizes up to 8 bytes. Find the + * right part. + */ + movq (%rdi),%r8 + movq (%rsi),%r9 + cmpq %r8,%r9 + jne 1f + leaq 8(%rdi),%rdi + leaq 8(%rsi),%rsi + jmp 1f +10163224: + leaq -8(%rdi,%rdx),%rdi + leaq -8(%rsi,%rdx),%rsi + jmp 1f +10163216: + leaq -16(%rdi,%rdx),%rdi + leaq -16(%rsi,%rdx),%rsi + jmp 1f +10163208: +10081608: + leaq 8(%rdi),%rdi + leaq 8(%rsi),%rsi + jmp 1f + +/* + * Mismatch was found. We have no more than 8 bytes to inspect. + */ +ALIGN_TEXT +1: + movzbl (%rdi),%eax + movzbl (%rsi),%r8d + cmpb %r8b,%al + jne 2f + + movzbl 1(%rdi),%eax + movzbl 1(%rsi),%r8d + cmpb %r8b,%al + jne 2f + + movzbl 2(%rdi),%eax + movzbl 2(%rsi),%r8d + cmpb %r8b,%al + jne 2f + + movzbl 3(%rdi),%eax + movzbl 3(%rsi),%r8d + cmpb %r8b,%al + jne 2f + + movzbl 4(%rdi),%eax + movzbl 4(%rsi),%r8d + cmpb %r8b,%al + jne 2f + + movzbl 5(%rdi),%eax + movzbl 5(%rsi),%r8d + cmpb %r8b,%al + jne 2f + + movzbl 6(%rdi),%eax + movzbl 6(%rsi),%r8d + cmpb %r8b,%al + jne 2f + + movzbl 7(%rdi),%eax + movzbl 7(%rsi),%r8d + cmpb %r8b,%al + jne 2f + + xorl %eax,%eax + ret +2: + subl %r8d,%eax + ret END(memcmp) .section .note.GNU-stack,"",%progbits