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#include <string.h>
#include <stdio.h>
#include "bcdfp.h"
/* very dumb and limited BCD floating point conversions.
they're written this way because they're only required to
support line numbers, and I don't want to have to link with
the math library (-lm). */
extern void die(const char *msg);
void die_range(void) {
die("Line number out of range (>65535)");
}
unsigned char bcd2int(unsigned char bcd) {
return (bcd >> 4) * 10 + (bcd & 0x0f);
}
unsigned char int2bcd(unsigned char i) {
return ((i / 10) << 4) | (i % 10);
}
unsigned short fp2int(const unsigned char *fp) {
unsigned int result = 0;
/* examine the exponent/sign byte */
if(fp[0] == 0) return 0; /* special case */
if(fp[0] & 0x80) die("Negative line numbers not supported");
switch(fp[0]) {
case 0x40:
result = bcd2int(fp[1]);
if(fp[2] >= 0x50) result++;
break;
case 0x41:
result = bcd2int(fp[1]) * 100 + bcd2int(fp[2]);
if(fp[3] >= 0x50) result++;
break;
case 0x42:
result = bcd2int(fp[1]) * 10000 + bcd2int(fp[2]) * 100 + bcd2int(fp[3]);
if(fp[4] >= 0x50) result++;
break;
default:
die_range(); break;
}
if(result > 0xffff) die_range();
return (unsigned short)result;
}
void int2fp(unsigned short num, unsigned char *fp) {
memset(fp, 0, 6);
if(num == 0) return;
if(num >= 10000) {
fp[0] = 0x42;
fp[3] = int2bcd(num % 100);
num /= 100;
fp[2] = int2bcd(num % 100);
num /= 100;
fp[1] = int2bcd(num);
} else if(num >= 100) {
fp[0] = 0x41;
fp[2] = int2bcd(num % 100);
num /= 100;
fp[1] = int2bcd(num);
} else {
fp[0] = 0x40;
fp[1] = int2bcd(num);
}
}
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