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#
# coswitch for the PowerPC architecture
#
.file "rswitch.s"
.data
errmsg: .string "new_context() returned in coswitch\n"
.text
.align 2
.globl coswitch
.type coswitch,@function
coswitch:
stwu 1, -80(1) # allocate stack frame
# Save Old Context:
stw 1, 0(3) # SP
mflr 0
stw 0, 4(3) # LR (return address)
stw 14, 0(1) # GPRs 14-31 (save on stack)
stw 15, 4(1)
stw 16, 8(1)
stw 17, 12(1)
stw 18, 16(1)
stw 19, 20(1)
stw 20, 24(1)
stw 21, 28(1)
stw 22, 32(1)
stw 23, 36(1)
stw 24, 40(1)
stw 25, 44(1)
stw 26, 48(1)
stw 27, 52(1)
stw 28, 56(1)
stw 29, 60(1)
stw 30, 64(1)
stw 31, 68(1)
cmpi 0, 5, 0
beq first # if first time
# Restore new context:
lwz 1, 0(4) # SP
lwz 0, 4(4) # LR
mtlr 0
lwz 14, 0(1) # GPRs 14-31 (from stack)
lwz 15, 4(1)
lwz 16, 8(1)
lwz 17, 12(1)
lwz 18, 16(1)
lwz 19, 20(1)
lwz 20, 24(1)
lwz 21, 28(1)
lwz 22, 32(1)
lwz 23, 36(1)
lwz 24, 40(1)
lwz 25, 44(1)
lwz 26, 48(1)
lwz 27, 52(1)
lwz 28, 56(1)
lwz 29, 60(1)
lwz 30, 64(1)
lwz 31, 68(1)
addic 1, 1, 80 # deallocate stack frame
blr # return into new context
first: # First-time call:
lwz 1, 0(4) # SP as figured by Icon
addic 1, 1, -64 # save area for callee
addi 3, 0, 0 # arg1
addi 4, 0, 0 # arg2
bl new_context # new_context(0,0)
lis 3, errmsg@ha
la 3, errmsg@l(3)
bl syserr
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