ack/mach/m68020/libem/sar.s
1987-01-29 22:10:18 +00:00

55 lines
1,002 B
ArmAsm

.define .sar
.sect .text
.sect .rom
.sect .data
.sect .bss
.sect .text
! (on entry d0 contains the integer size in the descriptor)
.sar:
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: return address
! For address calculation; see comment in 'aar.s'.
! If the element size is a fraction of EM_WSIZE (4)
! the calculation is done by adding.
move.l (sp)+, d2 ! return address
move.l (sp)+, a0
move.l (sp)+, d0
move.l (sp)+, a1
sub.l (a0), d0
move.l (8,a0), d1 ! # bytes / element
cmp.l #1, d1
bne 2f
move.l (sp)+, d1
move.b d1, (a1,d0.l) ! store one byte element
bra 5f
2:
cmp.l #2, d1
bne 4f
move.l (sp)+, d1
move.w d1, (a1,d0.l*2) ! store two byte element
bra 5f
4: ! here: 4n byte element
muls.l d1, d0
add.l d0, a1 ! address of 4n byte element
asr.l #2, d1
sub.l #1, d1
1:
move.l (sp)+, (a1)+
dbf d1, 1b
5:
move.l d2,a0
jmp (a0)
.align 2