22 lines
416 B
ArmAsm
22 lines
416 B
ArmAsm
.define Sbi2
|
|
|
|
! This subroutine subtracts two twobyte signed integers
|
|
! and returnes the result in registerpair AX.
|
|
|
|
|
|
Sbi2:
|
|
stx ARTH ! save second operand (lowbyte)
|
|
sta ARTH+1 ! save second operand (highbyte)
|
|
jsr Pop
|
|
pha
|
|
sec
|
|
txa ! get first operand (lowbyte)
|
|
sbc ARTH ! subtract second operand (lowbyte)
|
|
tax
|
|
iny
|
|
pla ! get first operand (highbyte)
|
|
sbc ARTH+1 ! subtract second operand (highbyte)
|
|
rts
|
|
|
|
|