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Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers...

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On Sunday, April 21, 2013 4:34:00 PM UTC+1, Coos Haak wrote:
> Op Fri, 19 Apr 2013 18:21:11 -0700 (PDT) schreef AKE:
> 
> > 	( Protect edx by saving to unused part of stack memory )
> > 	mov ebx, esp    
> > 	sub ebx, # 20   \ advance 5 cells ahead of current stack
> > 	mov [ebx], edx  \ save protected register edx
> > 	
> > 	( Run cpuid opcode )
<snip>
> > 	( Restore original value to edx from unused part of stack... )
> > 	mov ebx, esp
> > 	sub ebx, # 4   \ ... which has now grown by 4 cells
> > 	mov edx, [ebx] \ restore edx
> 
> 
> Use of the return stack to move edx out of the way, resulting in simpler
> and shorter code.
> 
> CODE call-cpu-info
> 	push ebx   \ preserve TOS
> 
> 	( Protect edx on the return stack )
>         sub ebp, # 4    \ Make room for edx
>         mov 0 [ebp], edx
> 
> 	( Run cpuid opcode )
> 	xor eax, eax   \ eax=0
> 	cpuid  	       \ returns eax=N (highest recognised param) 
> 		       \ and three packed 4-byte chars to ebx,ecx,edx
> 
> 	( Send returned values to Forth stack )
> 	push ecx  \ 'ntel'
> 	push edx  \ 'ineI'
> 	push ebx  \ 'Genu'
> 	push eax  \ highest recognised param
> 	
> 	( Restore original value to edx from the return stack )
> 	mov edx, 0 [ebp]  \ Restore edx
> 	add ebp, # 4
> 	next,
> end-code
> 



Coos --- 

Like it.  Hadn't thought of the return stack.  That's much better now.  Thanks! :)

- Assad

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Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... AKE <assadebrahim2000@gmail.com> - 2013-04-19 18:21 -0700
  Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... "Rod Pemberton" <do_not_have@notemailnotq.cpm> - 2013-04-21 01:27 -0400
    Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... AKE <assadebrahim2000@gmail.com> - 2013-04-21 04:57 -0700
      Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... "Rod Pemberton" <do_not_have@notemailnotq.cpm> - 2013-04-21 11:39 -0400
        Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... Alex McDonald <blog@rivadpm.com> - 2013-04-21 09:53 -0700
          Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... AKE <assadebrahim2000@gmail.com> - 2013-04-21 14:47 -0700
            Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... Alex McDonald <blog@rivadpm.com> - 2013-04-22 02:17 -0700
  Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... Coos Haak <chforth@hccnet.nl> - 2013-04-21 17:34 +0200
    Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... Coos Haak <chforth@hccnet.nl> - 2013-04-21 17:42 +0200
    Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-04-21 12:37 -0500
      Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... Alex McDonald <blog@rivadpm.com> - 2013-04-21 10:53 -0700
        Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-04-22 03:24 -0500
          Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... Alex McDonald <blog@rivadpm.com> - 2013-04-22 02:49 -0700
          Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-04-22 10:06 +0000
            Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-04-22 07:35 -0500
              Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-04-22 13:12 +0000
                Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-04-22 10:01 -0500
              Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... Alex McDonald <blog@rivadpm.com> - 2013-04-22 08:33 -0700
                Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-04-22 11:34 -0500
                Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... Alex McDonald <blog@rivadpm.com> - 2013-04-23 03:27 -0700
        Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... "Rod Pemberton" <do_not_have@notemailnotq.cpm> - 2013-04-23 17:42 -0400
          Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-04-24 03:00 -0500
      Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... AKE <assadebrahim2000@gmail.com> - 2013-04-21 14:43 -0700
        Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... Alex McDonald <blog@rivadpm.com> - 2013-04-22 02:21 -0700
          Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... Alex McDonald <blog@rivadpm.com> - 2013-04-22 08:36 -0700
            Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... Alex McDonald <blog@rivadpm.com> - 2013-04-22 08:39 -0700
              Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... AKE <assadebrahim2000@gmail.com> - 2013-04-22 13:55 -0700
    Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... AKE <assadebrahim2000@gmail.com> - 2013-04-21 14:39 -0700
  Re: Stack Interface between x86 Assembler & Forth -- technique when running out of unprotected registers... albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-04-21 21:00 +0000

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