98 lines
2.8 KiB
C
98 lines
2.8 KiB
C
// boostrap.c
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// Boostrapping Functions for the SplitBit CPU Emulator
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// Written by Anachronaut
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// 10/16/2024
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#include "bootstrap.h"
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#include <stdio.h>
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#include <string.h>
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int byte = 0;
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const uint8_t HEADER_LENGTH = 3; // Number of bytes for the header.
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const uint8_t LENGTH_SIZE = 2; // Number of bytes for the segment length.
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uint32_t readLength(FILE *file) {
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uint16_t length = 0;
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for (int i = 0; i < LENGTH_SIZE; i++) {
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int byte = fgetc(file);
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if (byte == EOF) {
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fprintf(stderr, "Error: Unexpected end of file while reading a segment length.\n");
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return UINT32_MAX;
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}
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length = (length << 8) | (uint8_t)byte;
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}
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return length;
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}
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uint32_t readHeader(FILE *file, const char *expectedHeader) {
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char header[HEADER_LENGTH];
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for (int i = 0; i < HEADER_LENGTH; i++) {
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int byte = fgetc(file);
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if (byte == EOF) {
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fprintf(stderr, "Error: Unexpected end of file while reading a header.\n");
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return UINT32_MAX;
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}
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header[i] = (uint8_t)byte;
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}
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if (strncmp(header, expectedHeader, 3)) {
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fprintf(stderr, "Error: Bad header.\n");
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printf("Header: %s\nExpected Header: %s\n", header, expectedHeader);
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return UINT32_MAX;
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}
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return 0;
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}
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uint8_t loadSegment(FILE *file, uint8_t *Memory, uint16_t length) {
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for (int16_t i = 0; i < length; i++) {
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byte = fgetc(file);
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if (byte == EOF) {
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fprintf(stderr, "Error: Unexpected end of file while reading a segment.\n");
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return 1;
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}
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Memory[i] = (uint8_t)byte;
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}
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return 0;
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}
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uint8_t loadFile(char *path, uint8_t *Program, uint8_t *Data) {
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FILE *file = fopen(path, "rb");
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if (file == NULL) {
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fprintf(stderr, "Error: Couldn't open file: %s\n", path);
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return 1;
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}
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// Read the first three bytes and check if they're the PRG header.
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if (readHeader(file, "PRG") == UINT32_MAX) {
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fclose(file);
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return 1;
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}
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// Now we need to get the length of the Program Section.
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uint32_t length = readLength(file);
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if (length == UINT32_MAX) {
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fclose(file);
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return 1;
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}
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// Now we load the Program Segment.
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if (loadSegment(file, Program, (uint16_t)length)) {
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fclose(file);
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return 1;
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}
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// Okay, Program is loaded, now do the same thing but for Data.
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// Check the header.
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if (readHeader(file, "DAT") == UINT32_MAX) {
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return 1;
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}
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// Get the legnth of the Data Section.
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length = readLength(file);
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if (length == UINT32_MAX){
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fclose(file);
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return 1;
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}
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// Now load the Data Section.
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if (loadSegment(file, Data, (uint16_t)length)) {
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fclose(file);
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return 1;
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}
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fclose(file);
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return 0;
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}
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