IDIV - x86 vs. x64

[Little John]

Hi,

I started ASM programming with 16 bit CPUs, later I wrote some small 32 bit ASM codes, and now I don't actually have a clue about 64 bit ASM.

Inspired by a 32 bit ASM code by Fred, I wrote the following code:

Code: Select all

; PB 5.31

Procedure.i AsmDiv (x.i, n.i)
   CompilerIf #PB_Compiler_Processor = #PB_Processor_x86
      ! MOV  eax, [p.v_x]
      ! MOV  ecx, [p.v_n]
      ! CDQ
      ! IDIV ecx
      ; ! MOV  eax, edx       ; uncomment this to make it REMAINDER instead of DIV
   CompilerElse
      ! MOV  rax, [p.v_x]
      ! MOV  rcx, [p.v_n]
      ! CQO
      ! IDIV rcx      
      ; ! MOV  rax, rdx       ; uncomment this to make it REMAINDER instead of DIV
   CompilerEndIf
   
   ProcedureReturn            ; result is in eax or rax, respectively 
EndProcedure


Debug AsmDiv( 17,  5)
Debug AsmDiv(-17,  5)
Debug AsmDiv( 17, -5)
Debug AsmDiv(-17, -5)

Is the code correct (for Windows, Mac, and Linux)?
Thanks in advance!

[wilbert]

Is the code correct (for Windows, Mac, and Linux)?

It looks fine to me.

[idle]

looks right to me, works fine x64 linux

[Little John]

Many thanks, wilbert and idle!