96 lines
2.5 KiB
C
96 lines
2.5 KiB
C
/*
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* File......: POKE.C
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* Author....: Ted Means
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* CIS ID....: 73067,3332
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*
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* This is an original work by Ted Means and is placed in the
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* public domain.
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*
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* Modification history:
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* ---------------------
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*
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* Rev 1.3 07 Feb 1994 20:13:22 GLENN
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* Ted re-wrote to make it CPMI compliant.
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*
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* Rev 1.2 15 Aug 1991 23:08:20 GLENN
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* Forest Belt proofread/edited/cleaned up doc
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*
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* Rev 1.1 14 Jun 1991 19:53:48 GLENN
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* Minor edit to file header
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*
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* Rev 1.0 01 Apr 1991 01:02:54 GLENN
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* Nanforum Toolkit
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*
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*
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*/
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/* $DOC$
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* $FUNCNAME$
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* FT_POKE()
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* $CATEGORY$
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* DOS/BIOS
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* $ONELINER$
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* Write a byte to a specified memory location
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* $SYNTAX$
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* FT_POKE( <nSegment>, <nOffset>, <nValue> ) -> lResult
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* $ARGUMENTS$
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* <nSegment> is the segment of the desired memory address.
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*
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* <nOffset> is the offset of the desired memory address.
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*
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* <nValue> is the value to write to the desired memory address.
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* $RETURNS$
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* <lResult> will be .T. if all parameters were valid and the function was
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* able to write the desired byte.
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* <lResult> will be .F. if invalid parameters were passed.
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* $DESCRIPTION$
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* Use this function if you have a need to change the value at a specific
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* memory location. The function will write the specified byte to the
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* specified address. The value must be passed as a numeric; if the byte
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* you wish to use is stored as a character, use the Asc() function
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* to convert it.
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*
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* This function was written for version 5.1 of MicroSoft C. You may
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* have to modify the source code to use another compiler.
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* $EXAMPLES$
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* FT_POKE( 0, 1047, 64) // Turn CapsLock on
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* $END$
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*/
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#include <extend.api>
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#include <cpmi.h>
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#define FP_SEG( fp ) ( *( ( unsigned int * ) &( fp ) + 1 ) )
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#define FP_OFF( fp ) ( *( ( unsigned int * ) &( fp ) ) )
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HB_FUNC( FT_POKE )
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{
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auto unsigned int ProtMode = hb_cpmiIsProtected();
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auto unsigned char * bytePtr;
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if ( ( PCOUNT >= 3 ) && ( ISNUM( 1 ) ) && ( ISNUM( 2 ) ) && ( ISNUM( 3 ) ) )
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{
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FP_SEG( bytePtr ) = _parni( 1 );
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FP_OFF( bytePtr ) = _parni( 2 );
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if ( ProtMode )
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{
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FP_SEG( bytePtr ) = hb_cpmiProtectedPtr( bytePtr, 1 );
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FP_OFF( bytePtr ) = 0;
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if ( FP_SEG( bytePtr ) == 0 ) goto Bogus;
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}
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*bytePtr = ( unsigned char ) _parni( 3 );
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if ( ProtMode ) hb_cpmiFreeSelector( FP_SEG( bytePtr ) );
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_retl( TRUE );
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}
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else
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Bogus: _retl( FALSE );
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return;
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}
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