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Make ASM memset for ARM return destination address, as is standard.

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@9519 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Thom Johansen 2006-04-05 15:41:07 +00:00
parent ffefe9237b
commit 872797be0e
1 changed files with 27 additions and 28 deletions
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55
firmware/common/memset_a.S
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@ -241,30 +241,29 @@ memset:
#elif defined(CPU_ARM)
/* The following code is taken from the Linux kernel version 2.6.15.3
/* The following code is based on code found in Linux kernel version 2.6.15.3
* linux/arch/arm/lib/memset.S
*
* Copyright (C) 1995-2000 Russell King
*/
@ .word 0
1: subs r2, r2, #4 @ 1 do we have enough
/* This code will align a pointer for memset, if needed */
1: cmp r2, #4 @ 1 do we have enough
blt 5f @ 1 bytes to align with?
cmp r3, #2 @ 1
strltb r1, [r0], #1 @ 1
strleb r1, [r0], #1 @ 1
strb r1, [r0], #1 @ 1
add r2, r2, r3 @ 1 (r2 = r2 - (4 - r3))
/*
* The pointer is now aligned and the length is adjusted. Try doing the
* memzero again.
*/
strgtb r1, [r0, #-1]! @ 1
strgeb r1, [r0, #-1]! @ 1
strb r1, [r0, #-1]! @ 1
sub r2, r2, r3 @ 1 r2 = r2 - r3
b 2f
.global memset
.type memset,%function
memset:
add r0, r0, r2 @ we'll write backwards in memory
ands r3, r0, #3 @ 1 unaligned?
bne 1b @ 1
2:
/*
* we know that the pointer in r0 is aligned to a word boundary.
*/
@ -272,7 +271,7 @@ memset:
orr r1, r1, r1, lsl #16
mov r3, r1
cmp r2, #16
blt 4f
blt 5f
/*
* We need an extra register for this loop - save the return address and
* use the LR
@ -281,36 +280,36 @@ memset:
mov ip, r1
mov lr, r1
2: subs r2, r2, #64
stmgeia r0!, {r1, r3, ip, lr} @ 64 bytes at a time.
stmgeia r0!, {r1, r3, ip, lr}
stmgeia r0!, {r1, r3, ip, lr}
stmgeia r0!, {r1, r3, ip, lr}
bgt 2b
3: subs r2, r2, #64
stmgedb r0!, {r1, r3, ip, lr} @ 64 bytes at a time.
stmgedb r0!, {r1, r3, ip, lr}
stmgedb r0!, {r1, r3, ip, lr}
stmgedb r0!, {r1, r3, ip, lr}
bgt 3b
ldmeqfd sp!, {pc} @ Now <64 bytes to go.
/*
* No need to correct the count; we're only testing bits from now on
*/
tst r2, #32
stmneia r0!, {r1, r3, ip, lr}
stmneia r0!, {r1, r3, ip, lr}
stmnedb r0!, {r1, r3, ip, lr}
stmnedb r0!, {r1, r3, ip, lr}
tst r2, #16
stmneia r0!, {r1, r3, ip, lr}
stmnedb r0!, {r1, r3, ip, lr}
ldr lr, [sp], #4
4: tst r2, #8
stmneia r0!, {r1, r3}
5: tst r2, #8
stmnedb r0!, {r1, r3}
tst r2, #4
strne r1, [r0], #4
strne r1, [r0, #-4]!
/*
* When we get here, we've got less than 4 bytes to zero. We
* may have an unaligned pointer as well.
*/
5: tst r2, #2
strneb r1, [r0], #1
strneb r1, [r0], #1
6: tst r2, #2
strneb r1, [r0, #-1]!
strneb r1, [r0, #-1]!
tst r2, #1
strneb r1, [r0], #1
strneb r1, [r0, #-1]!
mov pc, lr
end:
.size memset,.end-memset