kolibrios/programs/develop/ktcc/trunk/libc.obj/source/string/memset.s
turbocat cde4fa851d libc.obj:
- Formatted by clang-format (WebKit-style).
- Removed unnecessary errno linux. 
- Added KOS error codes. 
- String functions have been replaced with more optimal ones for x86. 
- Changed wrappers for 70 sysfunction.

git-svn-id: svn://kolibrios.org@9765 a494cfbc-eb01-0410-851d-a64ba20cac60
2022-04-15 09:00:55 +00:00

52 lines
1.0 KiB
ArmAsm
Executable File

/* Copyright (C) 1995 DJ Delorie, see COPYING.DJ for details */
.text
.align 4
.global memset
memset:
pushl %ebp
movl %esp,%ebp
pushl %edi
movl 8(%ebp),%edi
movl 12(%ebp),%eax
movl 16(%ebp),%ecx
cld
# We will handle memsets of <= 15 bytes one byte at a time.
# This avoids some extra overhead for small memsets, and
# knowing we are setting > 15 bytes eliminates some annoying
# checks in the "long move" case.
cmpl $15,%ecx
jle memset.L3
# Otherwise, tile the byte value out into %eax.
# 0x41 -> 0x41414141, etc.
movb %al,%ah
movl %eax,%edx
sall $16,%eax
movw %dx,%ax
jmp memset.L2
# Handle any cruft necessary to get %edi long-aligned.
memset.L1: stosb
decl %ecx
memset.L2: testl $3,%edi
jnz memset.L1
# Now slam out all of the longs.
movl %ecx,%edx
shrl $2,%ecx
rep
stosl
# Finally, handle any trailing cruft. We know the high three bytes
# of %ecx must be zero, so just put the "slop count" in the low byte.
movb %dl,%cl
andb $3,%cl
memset.L3: rep
stosb
popl %edi
movl 8(%ebp),%eax
leave
ret