ack/mach/i80/libem/ror4.s
1987-01-28 22:23:14 +00:00

53 lines
576 B
ArmAsm

.define .ror4
.sect .text
.sect .rom
.sect .data
.sect .bss
.sect .text
! Rotate 4 bytes right
! Expects in de-reg: number of rotates
! Expects on stack: operand
! Yields on stack: result
.ror4: pop h
shld .retadr
mov h,b
mov l,c
shld .bcreg
.ror4: pop h ! low-order bytes of operand
pop b ! high order bytes of operand
mov a,e
ani 31
jz 2f
mov e,a
mov a,l
rar
1: mov a,b
rar
mov b,a
mov a,c
rar
mov c,a
mov a,h
rar
mov h,a
mov a,l
rar
mov l,a
dcr e
jnz 1b ! keep looping
2: push b
push h
lhld .bcreg
mov b,h
mov c,l
lhld .retadr
pchl