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Re: How do I use #pragma aux with the HLT instruction?

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Am 09.10.19 um 19:31 schrieb Johann 'Myrkraverk' Oskarsson:
> Dear o.u.c_cpp,
> 
> How do I write a #pragma aux for the HLT instruction?  And how do I use
> said #pragma aux?  Are there any cotchas I need to be aware of when I
> use the HLT instruction?
> 
> For context, I'm writing a DOS extended program with CauseWay, and want
> to be nice to the CPU fan in my program's idle loop for people such as
> myself who run DOS operating systems in a virtual machine.
> 
> 
You have seen this info about Auxiliary Pragmas in the C Guide?

...
In the following DOS example, Open Watcom C/C++ will generate the
sequence of bytes following the "="
character in the auxiliary pragma whenever a call to mode4 is
encountered. mode4 is called an in-line
function.

void mode4(void);
#pragma aux mode4 =		\
	0xb4 0x00 /* mov AH,0 */ \
	0xb0 0x04 /* mov AL,4 */ \
	0xcd 0x10 /* int 10H */ \
	modify [ AH AL ];

The sequence in the above DOS example represents the following lines of
assembly language instructions.
	mov  AH,0  ; select function "set mode"
	mov  AL,4  ; specify mode (mode 4)
	int  10H   ; BIOS video call

The above example demonstrates how to generate BIOS function calls
in-line without writing an assembly
language function and calling it from your C/C++ program. The C
prototype for the function mode4 is not
necessary but is included so that we can take advantage of the argument
type checking provided by Open Watcom C/C++.
The following DOS example is equivalent to the above example but
mnemonics for the assembly language
instructions are used instead of the binary encoding of the assembly
language instructions.

void mode4(void);
#pragma aux mode4 =
	"mov AH,0",
	"mov AL,4",
	"int 10H"
	modify [ AH AL ];
...

CU/2
Frank

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How do I use #pragma aux with the HLT instruction? Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2019-10-10 01:31 +0800
  Re: How do I use #pragma aux with the HLT instruction? nospam_2019@efbe.prima.de - 2019-10-09 21:42 +0200
    Re: How do I use #pragma aux with the HLT instruction? Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2019-10-10 23:37 +0800
      Re: How do I use #pragma aux with the HLT instruction? Paul S Person <psperson1@ix.netcom.invalid> - 2019-10-10 09:07 -0700
        Re: How do I use #pragma aux with the HLT instruction? Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2019-10-11 00:18 +0800
          Re: How do I use #pragma aux with the HLT instruction? Frank Beythien <fbeythien@gmx.de> - 2019-10-10 18:43 +0200
      Re: How do I use #pragma aux with the HLT instruction? "Steven Levine" <steve53@nomail.earthlink.net> - 2019-10-12 16:55 +0000

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