; Assuming the address of the number to be converted from dec2bin is stored in A1
; the converted value will be stored in D1
Dec2bin move.l D2, -(A7) ; store values of registers to be used onto stack, so they arnt modified
move.l A1, -(A7)
dec2binloop move.b (A1)+, D2 ;move one byte into d2
cmp.l #0, d2 ; check to see if that byte is null
beq exit_dec2bin ; if the byte moved is 0, then we're at the end and exit the conversion
muls.l #10, D1 ;multiply final result by 10 to prepare for additional characters to be added.
sub.l #$30, D2 ; subtract 30 from byte moved
add.l d2, d1 ;add the resultant byte to the final result
jmp dec2binloop ;loop again, untill a null is found;
exit_dec2bin move.l (A7)+ , A1 ;restore registers to original value
move.l (A7)+ , D2
rts
******************************************
; wordsized binary number is stored in d1
; the address of the converted word is pointed at by A2 and onwards
bin2dec move.l D1, -(A7) ; store registers onto stack so they are not modified
move.l D2, -(A7)
move.l D3, -(A7)
move.l #0, -(a7) ; the stack will be used in this subroutine so add a null to separate used space and data to be not modified
move.l #10, D3 ; this register value will be used in the remu command
bin2decloop cmp.l #0, D1 ; see if the binary number is 0
beq reverse_chars ;if the binary number is 0, we are done and reverse the order
remu d3, d2:d1 ; else, divide the binary number by 10 and store the remainder in D2
add.l #$30, D2 ; add 30 to the remainder
move.l d2 -(a7) ; put the result onto the stack
jmp bin2decloop ;continue looping with the remaining binary words untill we hit 0.
reverse_chars cmp.l #0, (a7) ; see if the stack is at null, meaning we're at the end of our conversion;
beq exit_bin2dec ;if the stack is null, we are done and may restore original registers
move.l (A7)+, D2 ; move the value of the binary number into d2
move.b d2, (A2)+ ; now store the values that were in the stack in reverse order (in reverse order, we're popping the stack) into A2
jmp reverse_chars
exit_bind2dec move.l (A7)+,D2 ; pop the final null into the pointer A2 to signify the end of our conversion result
move.b D2, (A2)+
move.l (A7)+,D3 ; restore old values :)
move.l (A7)+,D2
move.l (A7)+,D1