ack/mach/i80/libem/sar2.s
1985-03-18 12:46:51 +00:00

69 lines
986 B
ArmAsm

.define .sar2
! Store array element, descriptor contains 2-bytes integers
! Expects on stack: pointer to array descriptor
! index
! base address
! array element
! Adapted from .aar2 and .sti
.sar2:
pop h
shld .retadr1
mov h,b
mov l,c
shld .bcreg
pop h ! hl = pointer to descriptor
pop d ! de = index
mov a,e ! bc = index - lower bound
sub m
inx h
mov c,a
mov a,d
sbb m
inx h
mov b,a
push b ! first operand to multiply
inx h
inx h
mov c,m ! bc = size
inx h
mov b,m
push b ! second operand to multiply
call .mli2 ! de = size * (index - lower bound)
pop h ! hl = base address
dad d ! hl = address of array[index]
xra a
mov a,b
rar
mov b,a
mov a,c
rar
mov c,a ! bc = word count
jnc 1f
! if 1 byte array element only:
mov a,c ! trap if bc odd and <>1
ora b
cnz eoddz
pop d
mov m,e
jmp 2f
1: pop d
mov m,e
inx h
mov m,d
inx h
dcx b
mov a,b
ora c
jnz 1b
2: lhld .bcreg
mov b,h
mov c,l
lhld .retadr1
pchl