mcopy dag.macros **************************************************************** * * 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 umod(x,y: longint): longint; * * Inputs: * num1 - numerator * num2 - denominator * * Outputs: * ans+4 - result * **************************************************************** * umod 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+4 move answer end **************************************************************** * * function umul(x,y: longint): longint; * * Inputs: * num2,num1 - operands * * Outputs: * ans - result * **************************************************************** * umul start ans equ 0 answer subroutine (4:num1,4:num2),8 ; ; Initialize the sign and split on precision. ; stz ans+4 set up the multiplier stz ans+6 lda num1 sta ans lda num1+2 sta ans+2 beq ml3 branch if the multiplier is 16 bit ; ; Do a 32 bit by 32 bit multiply. ; ldy #32 32 bit multiply jsr ml1 brl ml7 ml1 lda ans SYSS1*SYSS1+2+SYSS1+2 -> SYSS1,SYSS1+2 lsr a bcc ml2 clc add multiplicand to the partial product lda ans+4 adc num2 sta ans+4 lda ans+6 adc num2+2 sta ans+6 ml2 ror ans+6 shift the interem result ror ans+4 ror ans+2 ror ans dey loop til done bne ml1 rts ; ; Do and 16 bit by 32 bit multiply. ; ml3 lda num2+2 branch if 16x16 is possible beq ml4 ldy #16 set up for 16 bits jsr ml1 do the multiply lda ans+2 move the answer sta ans lda ans+4 sta ans+2 bra ml7 ; ; Do a 16 bit by 16 bit multiply. ; ml4 ldy #16 set the 16 bit counter ldx ans move the low word stx ans+2 ml5 lsr ans+2 test the bit bcc ml6 branch if the bit is off clc adc num2 ml6 ror a shift the answer ror ans dey loop bne ml5 sta ans+2 save the high word ; ; Return the result. ; ml7 return 4:ans fix the stack end