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readtape.c
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readtape.c
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#include <stdio.h>
#include <stdint.h>
#include "sdp8.h"
#include "memory.h"
#include "readtape.h"
//#define BUFSIZE 128
#define vprintf printf
//#define dprintf(...) do{}while(0)
// state definitions
#define IDLE 0
#define DATA 1
static unsigned char state;
/*
static void mem_write(uint16_t adr, uint16_t val)
{
vprintf("mem_write(0%04o)=0%04o\n", adr, val);
}
*/
/**
* a very simple scanner
*
* Ignores the leader part and stops at the trailer.
*
* @returns: a valid 13 bit value or EOF (-1)
*/
static int16_t read_word(FILE *fd)
{
int8_t v,w; // 8 bit signed is important
// ignore leader (ignore 0x80 bytes at beginning)
if (state==IDLE) {
do {
v = fgetc(fd);
DEBUG_PRINT("gotA 0%03o ", v);
if (v==(int8_t)-1) return EOF;
} while (v<0);//==0x80);
state = DATA;
} else {
v = fgetc(fd); // intentional downcast to 8 bit signed
DEBUG_PRINT("gotB 0%03o ", v);
}
if (v<0) return EOF; // This catches both, EOF and values >= 0x80
w = fgetc(fd);
DEBUG_PRINT("gotC 0%03o ", w);
if (w<0) return EOF;
return (v<<6) | (w & 0077);
}
int read_tape(char *name)
{
FILE *fd;
int16_t v;
uint16_t words, addr, max_addr;
fd = fopen(name,"rb");
if (!fd) return -1;
state = IDLE;
addr = 0;
words = 0;
max_addr= 0;
while ((v=read_word(fd))>=0) {//!=EOF) {
if (v & 010000) {
addr = v & 07777;
vprintf("set address to 0%04o\n", addr);
continue;
}
mem_write(addr, v);
// update the statistics
words++;
if (addr > max_addr) {
max_addr = addr;
}
addr++;
}
printf(
"read %d words from file %s, max. address 0%04o\n",
words, name, max_addr
);
}