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Optimise code a little.

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This commit is contained in:
Ulrich Drepper 2003-09-14 19:54:53 +00:00
parent 2c65912458
commit 60f4eece70
1 changed files with 22 additions and 16 deletions
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38
sysdeps/unix/sysv/linux/arm/mmap64.S
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@ -27,38 +27,44 @@
.text
ENTRY (__mmap64)
#ifdef __NR_mmap2
stmfd sp!, {r4, r5, lr}
ldr r5, [sp, $16]
ldr r4, [sp, $12]
movs ip, r5, lsl $20 @ check that offset is page-aligned
ldr ip, [sp, $4] @ offset low part
str r5, [sp, #-4]!
ldr r5, [sp, $12] @ offset high part
str r4, [sp, #-4]!
movs r4, ip, lsl $20 @ check that offset is page-aligned
mov ip, ip, lsr $12
moveqs r4, r5, lsr $12 @ check for overflow
bne .Linval
ldr ip, [sp, $20]
mov r5, r5, lsr $12
orr r5, r5, ip, lsl $20 @ compose page offset
movs ip, ip, lsr $12
bne .Linval @ check for overflow
ldr r4, [sp, $8] @ load fd
orr r5, ip, r5, lsl $20 @ compose page offset
mov ip, r0
swi SYS_ify (mmap2)
cmn r0, $4096
LOADREGS(ccfd, sp!, {r4, r5, pc})
# ifdef __ASSUME_MMAP2_SYSCALL
ldmfd sp!, {r4, r5, lr}
ldr r4, [sp], #4
ldr r5, [sp], #4
RETINSTR(movcc, pc, lr)
b PLTJMP(syscall_error)
# else
ldrcc r4, [sp], #4
ldrcc r5, [sp], #4
RETINSTR(movcc, pc, lr)
cmn r0, $ENOSYS
ldmnefd sp!, {r4, r5, lr}
bne PLTJMP(syscall_error)
bne .Lerror
/* The current kernel does not support mmap2. Fall back to plain
mmap if the offset is small enough. */
ldr r5, [sp, $20]
ldr r5, [sp, $16]
mov r0, ip @ first arg was clobbered
teq r5, $0
ldmeqfd sp!, {r4, r5, lr}
ldreq r4, [sp], #4
ldreq r5, [sp], #4
beq PLTJMP(__mmap)
# endif
.Linval:
mov r0, $-EINVAL
ldmfd sp!, {r4, r5, lr}
.Lerror:
ldr r4, [sp], #4
ldr r5, [sp], #4
b PLTJMP(syscall_error)
#else
/* The kernel headers do not support mmap2. Fall back to plain