33 lines
849 B
C
33 lines
849 B
C
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/*
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SCREEN.C - This example shows how to write directly
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to screen memory under the DOS/4GW dos-extender.
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Compile & Link: wcl386 /l=dos4g SCREEN
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*/
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#include <stdio.h>
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#include <dos.h>
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/*
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Under DOS/4GW, the first megabyte of physical memory - the
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real memory - is mapped as a shared linear address space.
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This allows your application to access video RAM using its
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linear address. The DOS segment:offset of B800:0000
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corresponds to a linear address of B8000.
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*/
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#define SCREEN_AREA 0xb800
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#define SCREEN_LIN_ADDR ((SCREEN_AREA) << 4)
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#define SCREEN_SIZE 80*25
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void main()
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{
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char *ptr;
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int i;
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/* Set the pointer to the screen's linear address */
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ptr = (char *)SCREEN_LIN_ADDR;
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for( i = 0; i < SCREEN_SIZE - 1; i++ ) {
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*ptr = '*';
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ptr += 2 * sizeof( char );
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}
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}
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