signed multiply/divide in assembly

Graham Stabler

Before I code it myself, is it already available?

Cheers,

Graham

max72

There are samples on the wikispaces..

http://propeller.wikispaces.com/MATH

Massimo

Bean

Here is the code generated by PropBasic.

                  mov           __temp1,__param2             '  __param1 = __param2 * __param3
                  mov           __temp2,__param3            
                  abs           __temp1,__temp1 WC          
                  muxc          __temp3,#1                  
                  abs           __temp2,__temp2 WC, WZ      
    IF_C          xor           __temp3,#1                  
                  mov           __temp4,#0                  
                  mov           __temp5,#32                 
                  shr           __temp1,#1 WC               
__L0001                                                     
    IF_C          add           __temp4,__temp2 WC          
                  rcr           __temp4,#1 WC               
                  rcr           __temp1,#1 WC               
                  djnz          __temp5,#__L0001            
                  test          __temp3,#1 WZ               
    IF_NZ         neg           __temp4,__temp4             
    IF_NZ         neg           __temp1,__temp1 WZ          
    IF_NZ         sub           __temp4,#1                  
                  mov           __param1,__temp1            


                  mov           __temp1,__param2             '  __param1 = __param2 / __param3
                  mov           __temp2,__param3            
                  mov           __temp4,#0                  
                  abs           __temp1,__temp1 WC          
                  muxc          __temp5,#1                  
                  abs           __temp2,__temp2 WC, WZ      
    IF_Z          mov           __temp1,#0                  
    IF_Z          jmp           #__L0002                    
    IF_C          xor           __temp5,#1                  
                  mov           __temp3,#0                  
                  min           __temp2,#1                  
__L0003                                                     
                  add           __temp3,#1                  
                  shl           __temp2,#1 WC               
    IF_NC         jmp           #__L0003                    
                  rcr           __temp2,#1                  
__L0004                                                     
                  cmpsub        __temp1,__temp2 WC          
                  rcl           __temp4,#1                  
                  shr           __temp2,#1                  
                  djnz          __temp3,#__L0004            
                  test          __temp5,#1 WZ               
    IF_NZ         neg           __temp4,__temp4             
    IF_NZ         neg           __temp1,__temp1             
__L0002                                                     
                  mov           __param1,__temp4            

BR

See attached rabble of ASM snippets...lines 7-39. Also lines 398-449.

Sorry about the thread links embedded in the comments, they're from the old forum. You'll have to use Phil's thread converter to see the original threads.

I dunno why there isn't a nice sticky somewhere that compiles a bunch of useful ASM snippets in one place...

Cluso99

IIRC the spin interpreter is signed mult and divide. You can find the original code of the interpreter posted by Chip. There is a faster version in my spin interpreter (IIRC Chip provided the mult improvement - its noted in the code anyway).
To find may faster spin interpreter, follow the Tools link in my signature.

Graham Stabler

Thanks guys, I've not had a chance to follow up the leads but it looks really promising, I'll get back to you when I can, typically I have lots of paper work to do instead of coding

Graham