signed multiply/divide in assembly

Comments

• max72 Posts: 1,155

  2011-03-03 09:04 edited 2011-03-03 09:04

  There are samples on the wikispaces..
  
  http://propeller.wikispaces.com/MATH
  
  Massimo
• Bean Posts: 8,129

  2011-03-03 11:52 edited 2011-03-03 11:52

  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 Posts: 92

  2011-03-03 19:15 edited 2011-03-03 19:15

  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...

  spin

  spin

  asm_subroutine_snippets.spin

  104K

  asm_subroutine_snippets.spin 104.3K
• Cluso99 Posts: 18,069

  2011-03-04 01:45 edited 2011-03-04 01:45

  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 Posts: 2,510

  2011-03-04 04:35 edited 2011-03-04 04:35

  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