91 lines
2.4 KiB
C
91 lines
2.4 KiB
C
/*
|
|
* File......: PEEK.C
|
|
* Author....: Ted Means
|
|
* CIS ID....: 73067,3332
|
|
*
|
|
* This function is an original work by Ted Means and is placed in the
|
|
* public domain.
|
|
*
|
|
* Modification history:
|
|
* ---------------------
|
|
*
|
|
* Rev 1.3 07 Feb 1994 20:11:50 GLENN
|
|
* Ted re-wrote to make it CPMI compliant.
|
|
*
|
|
* Rev 1.2 15 Aug 1991 23:08:18 GLENN
|
|
* Forest Belt proofread/edited/cleaned up doc
|
|
*
|
|
* Rev 1.1 14 Jun 1991 19:53:46 GLENN
|
|
* Minor edit to file header
|
|
*
|
|
* Rev 1.0 01 Apr 1991 01:02:52 GLENN
|
|
* Nanforum Toolkit
|
|
*
|
|
*
|
|
*/
|
|
|
|
|
|
/* $DOC$
|
|
* $FUNCNAME$
|
|
* FT_PEEK()
|
|
* $CATEGORY$
|
|
* DOS/BIOS
|
|
* $ONELINER$
|
|
* Retrieve a byte from a specified memory location.
|
|
* $SYNTAX$
|
|
* FT_PEEK( <nSegment>, <nOffset> ) -> nValue
|
|
* $ARGUMENTS$
|
|
* <nSegment> is the segment of the desired memory address.
|
|
*
|
|
* <nOffset> is the offset of the desired memory address.
|
|
* $RETURNS$
|
|
* <nValue> will be a value from 0 to 255 if all parameters were valid and
|
|
* the function was able to retrieve the desired byte.
|
|
* <nValue> will be -1 if invalid parameters were passed.
|
|
* $DESCRIPTION$
|
|
* Use this function if you have a need to examine a specific memory
|
|
* location. The function will return the byte at the specified
|
|
* address as a numeric value. If you need this value as a character,
|
|
* use the Chr() function to convert it.
|
|
*
|
|
* This function was written for version 5.1 of MicroSoft C. You may
|
|
* have to modify the source code to use another compiler.
|
|
* $EXAMPLES$
|
|
* local nVMode := FT_PEEK( 0, 1097 ) // Get the current video mode
|
|
* $END$
|
|
*/
|
|
|
|
#include <extend.api>
|
|
#include <cpmi.h>
|
|
|
|
#define FP_SEG( fp ) ( *( ( unsigned int * ) &( fp ) + 1 ) )
|
|
#define FP_OFF( fp ) ( *( ( unsigned int * ) &( fp ) ) )
|
|
|
|
HB_FUNC(FT_PEEK)
|
|
{
|
|
auto unsigned int ProtMode = cpmiIsProtected();
|
|
auto unsigned char * bytePtr;
|
|
|
|
if ( ( PCOUNT >= 2 ) && ( ISNUM( 1 ) ) && ( ISNUM( 2 ) ) )
|
|
{
|
|
FP_SEG( bytePtr ) = _parni( 1 );
|
|
FP_OFF( bytePtr ) = _parni( 2 );
|
|
|
|
if ( ProtMode )
|
|
{
|
|
FP_SEG( bytePtr ) = hb_cpmiProtectedPtr( bytePtr, 1 );
|
|
FP_OFF( bytePtr ) = 0;
|
|
|
|
if ( FP_SEG( bytePtr ) == 0 ) goto Bogus;
|
|
}
|
|
|
|
_retni( ( int ) *bytePtr );
|
|
|
|
if ( ProtMode ) hb_cpmiFreeSelector( FP_SEG( bytePtr ) );
|
|
}
|
|
else
|
|
Bogus: _retni( -1 );
|
|
|
|
return;
|
|
}
|