mirror of
https://github.com/cc65/cc65.git
synced 2024-10-31 20:06:11 +00:00
102 lines
3.7 KiB
C
102 lines
3.7 KiB
C
// --------------------------------------------------------------------------
|
|
// Sym-1 Extended Memory
|
|
//
|
|
// Wayne Parham
|
|
//
|
|
// wayne@parhamdata.com
|
|
// --------------------------------------------------------------------------
|
|
//
|
|
// Note: This program examines memory above the monitor ROM (8000-8FFF) to
|
|
// Determine what, if any, memory is available. It then adds whatever
|
|
// 4K segments it finds to the heap.
|
|
//
|
|
// Memory Segment Remark
|
|
// 0x9000 Usually available
|
|
// 0xA000 System I/O, always unavailable
|
|
// 0xB000 Used by RAE, but normally available
|
|
// 0xC000 Used by BASIC, normally unavailable
|
|
// 0xD000 Used by BASIC, normally unavailable
|
|
// 0xE000 Used by RAE, but normally available
|
|
// 0xF000 Normally available, but only to FF7F
|
|
//
|
|
// --------------------------------------------------------------------------
|
|
|
|
#include <sym1.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
|
|
#define STD_MEM 0x7FFF // Last address of standard memory
|
|
#define SEGMENT 0x9000 // First 4K segment of extended memory
|
|
#define SEG_END 0x0FFF // Last location of segment
|
|
#define BLOCK_SIZE 0x1000 // Size of segment
|
|
#define TOP_END 0x0F7F // Last location of memory
|
|
#define TOP_SIZE 0x0F80 // Size of top segment
|
|
#define UNAVAILABLE 0xA000 // System I/O area
|
|
|
|
int main (void) {
|
|
int error = 0;
|
|
unsigned heap_size = 0x0000;
|
|
char* segment = (char*) SEGMENT;
|
|
|
|
printf ( "Analyzing memory.\n\n" );
|
|
|
|
heap_size = _heapmemavail();
|
|
|
|
printf ( "Main memory has %u bytes available.\n", heap_size );
|
|
|
|
if ( heap_size > STD_MEM ) {
|
|
printf ( "Extended memory already installed.\n" );
|
|
} else {
|
|
|
|
while ( (int) segment < 0xEFFF ) { // Iterate through 4K memory blocks
|
|
if( (int) segment != UNAVAILABLE ) {
|
|
segment[0] = 0x00; // Check beginning of segment
|
|
if ( segment[0] != 0x00 )
|
|
error = 1;
|
|
segment[0] = 0xFF;
|
|
if ( segment[0] != 0xFF )
|
|
error = 1;
|
|
segment[SEG_END] = 0x00; // Check end of segment
|
|
if ( segment[SEG_END] != 0x00 )
|
|
error = 1;
|
|
segment[SEG_END] = 0xFF;
|
|
if ( segment[SEG_END] != 0xFF )
|
|
error = 1;
|
|
if ( ! error ) { // If memory found, add to the heap
|
|
printf ( "Memory found at location %p, ", segment );
|
|
_heapadd ( segment, BLOCK_SIZE );
|
|
heap_size = _heapmemavail();
|
|
printf( "so the system now has %u bytes available.\n", heap_size );
|
|
} else {
|
|
error = 0;
|
|
}
|
|
}
|
|
segment += 0x1000; // Increment to next segment
|
|
}
|
|
|
|
segment[0] = 0x00; // Check beginning of top memory segment
|
|
if ( segment[0] != 0x00 )
|
|
error = 1;
|
|
segment[0] = 0xFF;
|
|
if ( segment[0] != 0xFF )
|
|
error = 1;
|
|
segment[TOP_END] = 0x00; // Check end of usable memory
|
|
if ( segment[TOP_END] != 0x00 )
|
|
error = 1;
|
|
segment[TOP_END] = 0xFF;
|
|
if ( segment[TOP_END] != 0xFF )
|
|
error = 1;
|
|
if ( ! error ) { // If memory found, add to the heap
|
|
printf ( "Memory found at location %p, ", segment );
|
|
_heapadd ( segment, TOP_SIZE );
|
|
heap_size = _heapmemavail();
|
|
printf( "so the system now has %u bytes available.\n", heap_size );
|
|
}
|
|
}
|
|
|
|
puts ("\nEnjoy your day!\n");
|
|
|
|
return 0;
|
|
}
|