1 line
9.3 KiB
NASM
1 line
9.3 KiB
NASM
|
mcopy exp.macros
****************************************************************
*
* function lshr(x,y: longint): longint;
*
* Inputs:
* num1 - number to shift
* num2 - # bits to shift by
*
* Outputs:
* A - result
*
****************************************************************
*
lshr start
subroutine (4:num1,4:num2),0
lda num2+2 if num2 < 0 then
bpl lb2
cmp #$FFFF shift left
bne zero
ldx num2
cpx #-34
blt zero
lb1 asl num1
rol num1+2
inx
bne lb1
bra lb4
zero stz num1 (result is zero)
stz num1+2
bra lb4
lb2 bne zero else shift right
ldx num2
beq lb4
cpx #33
bge zero
lb3 lsr num1+2
ror num1
dex
bne lb3
lb4 lda 0 fix stack and return
sta num2
lda 2
sta num2+2
return 4:num1
end
****************************************************************
*
* function udiv(x,y: longint): longint;
*
* Inputs:
* num1 - numerator
* num2 - denominator
*
* Outputs:
* ans - result
*
****************************************************************
*
udiv start
ans equ 0 answer
rem equ 4 remainder
subroutine (4:num1,4:num2),8
;
; Initialize
;
stz rem rem = 0
stz rem+2
move4 num1,ans ans = num1
lda num2 check for division by zero
ora num2+2
beq dv9
lda num2+2 do 16 bit divides separately
ora ans+2
beq dv5
;
; 32 bit divide
;
ldy #32 32 bits to go
dv3 asl ans roll up the next number
rol ans+2
rol ans+4
rol ans+6
sec subtract for this digit
lda ans+4
sbc num1
tax
lda ans+6
sbc num2+2
bcc dv4 branch if minus
stx ans+4 turn the bit on
sta ans+6
inc ans
dv4 dey next bit
bne dv3
bra dv9 go do the sign
;
; 16 bit divide
;
dv5 lda #0 initialize the remainder
ldy #16 16 bits to go
dv6 asl ans roll up the next number
rol a
sec subtract the digit
sbc num2
bcs dv7
adc num2 digit is 0
dey
bne dv6
bra dv8
dv7 inc ans digit is 1
dey
bne dv6
dv8 sta ans+4 save the remainder
;
; Return the result
;
dv9 return 4:ans move answer
end
****************************************************************
*
* function uge(x,y: longint): cboolean;
*
****************************************************************
*
uge start
result equ 0
subroutine (4:x,4:y),4
stz result
stz result+2
lda x+2
cmp y+2
bne lb1
lda x
cmp y
lb1 blt lb2
dec result
dec result+2
lb2 return 2:result
end
****************************************************************
*
* function ugt(x,y: longint): cboolean;
*
****************************************************************
*
ugt start
result equ 0
subroutine (4:x,4:y),4
stz result
stz result+2
lda x+2
cmp y+2
bne lb1
lda x
cmp y
lb1
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