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backported fixes from 256boss
[bootcensus]
/
src
/
libc
/
string_asm.s
diff --git
a/src/libc/string_asm.s
b/src/libc/string_asm.s
index
ce9b19a
..
a15a405
100644
(file)
--- a/
src/libc/string_asm.s
+++ b/
src/libc/string_asm.s
@@
-22,6
+22,7
@@
memset:
push %edi
mov 8(%ebp), %edi
push %edi
mov 8(%ebp), %edi
+ push %edi
mov 12(%ebp), %al
mov %al, %ah
mov %ax, %cx
mov 12(%ebp), %al
mov %al, %ah
mov %ax, %cx
@@
-32,26
+33,29
@@
memset:
cmp $0, %ecx
jz msdone
cmp $0, %ecx
jz msdone
+ # write 1, 2, or 3 times until we reache a 32bit-aligned dest address
mov %edi, %edx
and $3, %edx
jz msmain
jmp *mspre_tab(,%edx,4)
mspre_tab: .long msmain, mspre1, mspre2, mspre3
mov %edi, %edx
and $3, %edx
jz msmain
jmp *mspre_tab(,%edx,4)
mspre_tab: .long msmain, mspre1, mspre2, mspre3
-mspre1: stosb
+mspre3: stosb
dec %ecx
mspre2: stosb
dec %ecx
dec %ecx
mspre2: stosb
dec %ecx
-mspre3: stosb
+mspre1: stosb
dec %ecx
jz msdone
dec %ecx
jz msdone
+ # edi is 32bit-aligned here, write ecx>>2 32bit values
msmain:
push %ecx
shr $2, %ecx
rep stosl
pop %ecx
msmain:
push %ecx
shr $2, %ecx
rep stosl
pop %ecx
+ # write any trailing bytes
and $3, %ecx
jmp *mspost_tab(,%ecx,4)
and $3, %ecx
jmp *mspost_tab(,%ecx,4)
@@
-61,6
+65,7
@@
mspost2:stosb
mspost1:stosb
msdone:
mspost1:stosb
msdone:
+ pop %eax
pop %edi
pop %ebp
ret
pop %edi
pop %ebp
ret
@@
-75,6
+80,7
@@
memset16:
push %edi
mov 8(%ebp), %edi
push %edi
mov 8(%ebp), %edi
+ push %edi
mov 12(%ebp), %ax
shl $16, %eax
mov 12(%ebp), %ax
mov 12(%ebp), %ax
shl $16, %eax
mov 12(%ebp), %ax
@@
-127,7
+133,7
@@
ms16main:
jz ms16done
stosw
ms16done:
jz ms16done
stosw
ms16done:
-
+ pop %eax
pop %edi
pop %ebp
ret
pop %edi
pop %ebp
ret