I completed a M3 project with much help from this forum. Thanks again.

Now I am tasked with porting to the M0 (NXP 1114).

So upfront I suck at math. That is what got me in microprocessors!

My port is stalled at commented out UDIV and MLS opcodes that don't exist in MO...

Any help including equivalent code to tutorials on how to do the math would be appreciated by me.

Thanks in Advance.

P.S. I hope Revolution is in good health and spirits and I am still scared to solve your puzzle!

For UDIV you could modify this ARM code for THUMB. Be careful about the size of the repeat loop, with thumb code you might need to check the output to see that you get what is expected with regard to instruction lengths:

Code:

divide_unsigned:     numerator equ r0     denominator equ r1         cmp     denominator,0         beq     .divide_by_0         subs    ip,numerator,denominator         blo     .smaller_than_1         cmp     ip,denominator         blo     .is_1         mov     r3,numerator         clz     ip,numerator         clz     r2,denominator         sub     ip,r2,ip         rsbs    ip,ip,31         addne   ip,ip,ip,lsl 1                  ;ip * 3         mov     r0,0         addne   pc,pc,ip,lsl 2         nop         .rotate = 32         while .rotate>0                 .rotate = .rotate - 1                 cmp     r3,denominator,lsl .rotate                 adc     r0,r0,r0                 subcs   r3,r3,denominator,lsl .rotate         end while         mov     r1,r3                           ;remainder         mov     pc,lr     .smaller_than_1:         mov     r1,numerator                    ;remainder         mov     r0,0                            ;result         mov     pc,lr     .is_1:         sub     r1,numerator,denominator        ;remainder         mov     r0,1                            ;result         mov     pc,lr     .divide_by_0:         mov     r1,numerator                    ;remainder         mov     r0,-1                           ;result = infinity         mov     pc,lr

For MLS it should be no difficulty to use two instructions; MUL then SUB. I can't see how that is causing a problem unless I misunderstand your description.

This gets put in an interpreter wrapper so I should be able to test effectively. I also am blessed to have a black box model to check against.

Thanks so much!

Clyde

I'm not familiar with what the ip is.