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Use r12 as a temporary register in setrunqueue() and remrunqueue() as it

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does not need to be preserved across function calls. This means the use
of r4 can be eliminated thus saving a stack push and pop for r4.
This commit is contained in:
mark 1998-04-20 17:27:30 +00:00
parent 761ce530bb
commit 7782adb98e
1 changed files with 9 additions and 16 deletions
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25
sys/arch/arm32/arm32/cpuswitch.S
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@ -1,4 +1,4 @@
/* $NetBSD: cpuswitch.S,v 1.21 1998/04/19 23:37:22 mark Exp $ */
/* $NetBSD: cpuswitch.S,v 1.22 1998/04/20 17:27:30 mark Exp $ */
/*
* Copyright (c) 1994-1997 Mark Brinicombe.
@ -97,10 +97,8 @@ ENTRY(setrunqueue)
* r1 = queue
* r2 = &qs[queue] and temp
* r3 = temp
* r4 = whichqs
* r12 = whichqs
*/
stmfd sp!, {r4}
#ifdef DIAGNOSTIC
ldr r1, [r0, #(P_BACK)]
teq r1, #0x00000000
@ -116,12 +114,12 @@ ENTRY(setrunqueue)
mov r1, r1, lsr #2
/* Indicate that there is a process on this queue */
ldr r4, Lwhichqs
ldr r2, [r4]
ldr r12, Lwhichqs
ldr r2, [r12]
mov r3, #0x00000001
mov r3, r3, lsl r1
orr r2, r2, r3
str r2, [r4]
str r2, [r12]
/* Get the address of the queue */
ldr r2, Lqs
@ -139,8 +137,6 @@ ENTRY(setrunqueue)
str r0, [r2, #(P_FORW)]
str r2, [r0, #(P_BACK)]
ldmfd sp!, {r4}
mov pc, lr
#ifdef DIAGNOSTIC
@ -174,9 +170,8 @@ ENTRY(remrunqueue)
* r1 = queue
* r2 = &qs[queue] and scratch
* r3 = scratch
* r4 = whichqs
* r12 = whichqs
*/
stmfd sp!, {r4}
/* Get the priority of the queue */
ldrb r1, [r0, #(P_PRIORITY)]
@ -193,19 +188,17 @@ ENTRY(remrunqueue)
teq r2, r3
/* This could be reworked to avoid the use of r4 */
ldreq r4, Lwhichqs
ldreq r2, [r4]
ldreq r12, Lwhichqs
ldreq r2, [r12]
moveq r3, #0x00000001
moveq r3, r3, lsl r1
biceq r2, r2, r3
streq r2, [r4]
streq r2, [r12]
/* Remove the back pointer for the process */
mov r1, #0x00000000
str r1, [r0, #(P_BACK)]
ldmfd sp!, {r4}
mov pc, lr