ack/mach/m68020/libem/lar.s

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ArmAsm
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1987-01-29 22:10:18 +00:00
.define .lar
.sect .text
.sect .rom
.sect .data
.sect .bss
.sect .text
! (on entry d0 contains the integer size in the descriptor)
.lar:
cmp.l #4, d0
beq 9f
move.l #EILLINS, -(sp)
jmp (.fatal)
9:
! register usage:
! a0: descriptor address
! a1: base address
! d0: index
! d1: # bytes / element
! d2: save return address
! For address calculation; see comment in 'aar.s'.
move.l (sp)+, d2 ! return address
move.l (sp)+, a0 ! descriptor address
move.l (sp)+, d0 ! index
move.l (sp)+, a1 ! array base address
sub.l (a0), d0 ! relative index
move.l (8,a0), d1 ! # bytes / element
cmp.l #1, d1
bne 2f
clr.l -(sp)
move.b (a1,d0.l), (3,sp) ! one byte element
bra 5f
2:
cmp.l #2, d1
bne 4f
clr.l -(sp)
move.w (a1,d0.l*2), (2,sp) ! two byte element
bra 5f
4:
muls.l d1, d0
add.l d0, a1 ! address of 4n byte element
add.l d1, a1 ! because of predecrement
asr.l #2, d1
sub.l #1, d1
1:
move.l -(a1), -(sp)
dbf d1, 1b
5:
move.l d2,a0
jmp (a0)
.align 2