ack/mach/m68k4/libem/lar.s

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1987-03-27 09:47:16 +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, later base addres
! a1: return address
! d0: index
! d2: #bytes / element
! For address calculation; see comment in 'aar.s'.
move.l (sp)+, a1 ! return address
move.l (sp)+, a0 ! descriptor address
move.l (sp)+, d0 ! index
sub.l (a0), d0 ! relative index
move.l 8(a0), d2 ! #bytes / element
move.l (sp)+, a0 ! array base address
clr.l d1
cmp.l #1, d2
bne 2f
move.b 0(a0, d0.l), d1 ! one byte element
move.l d1, -(sp)
bra 5f
2:
cmp.l #2, d2
bne 4f
asl.l #1, d0
move.w 0(a0, d0.l), d1 ! two byte element
move.l d1, -(sp)
bra 5f
4:
move.l a0,-(sp)
move.l d0, -(sp)
move.l d2, -(sp)
jsr .mlu
move.l (sp)+,a0
add.l d1, a0 ! address of 4n byte element
add.l d2, a0 ! because of predecrement
asr.l #2, d2
sub.l #1, d2
1:
move.l -(a0), -(sp)
dbf d2, 1b
5:
jmp (a1)
.align 2