Category : Printer + Display Graphics
Archive : AI32BT.ZIP
Filename : XBIT.C
Output of file : XBIT.C contained in archive : AI32BT.ZIP
#include
#include
#include "xbit.h"
int
XBits, XBytes, IntXBits, DecXBits, ParDecXBits, ParDecXBytes,
MultShiftBits, MultBytes, XBitOverflow, XBitSign;
void SetXBit(int Bytes, int IntBits) {
XBytes = Bytes + 1;
XBytes >>= 1;
XBytes <<= 1;
XBits = Bytes << 3;
IntXBits = IntBits;
DecXBits = XBits - (IntBits + 1);
ParDecXBytes = DecXBits >> 3;
ParDecXBits = DecXBits & 7;
MultBytes = IntBits >> 3;
MultShiftBits = IntBits & 7;
}
int DoubleToXBit(double d, XBIT x) {
char Signed, dc[10];
int *di, Underflow;
/* 1. Setup integer alias */
di = (int*)dc;
/* 2. Clear 'x' */
strnset(x, 0, XBytes);
/* 3. Copy 'd' to char buffer */
memcpy(&dc[2], (char*)&d, 8);
di[0] = 0;
/* 4. Get and mask the sign bit */
Signed = dc[9] &0x80;
dc[9] &= 0x7f;
/* 5. Separate exponent from mantisa */
XBitShift(dc, 10, -4);
/* 6. Check for double = 0 (i.e. exponent = 0) */
if(!di[4])
return(0);
/* 7. Convert negative biased mantisa (ranged from 1.0 to 2.0)
and make room for sign bit */
XBitShift(dc, 8, -2);
dc[7] |= 0x40;
/* 8. Convert excess 1023 exponent to deficit 'IntXBits - 1' */
di[4] -= 1023 + (XBits - DecXBits - 2);
/* 9. Check for Overflow */
if(di[4] > 0)
return(di[4]);
/* 10. Check for Underflow */
Underflow = di[4] + XBits;
if(Underflow < 0)
return(Underflow);
/* 11. Move mantisa to 'x' */
if(XBytes >= 8)
memcpy(&x[XBytes - 8], dc, 8);
else
memcpy(x, &dc[8 - XBytes], XBytes);
/* 12. Right bit shift 'x' by exponent */
XBitShift(x, XBytes, di[4]);
/* 13. Negate 'x' if 'd' was signed */
if(Signed)
return(XBitNegate(x, XBytes));
else
return(0);
}
/* Not used by Malderbot draw program, but helps out in debugging */
double XBitToDouble(XBIT XBit) {
char *dc, *x;
double d = 0.0;
int Exponent, *di;
unsigned Sign;
dc = (char*)&d;
di = (int*)dc;
x = malloc(XBytes);
memcpy(x, XBit, XBytes);
if(x[XBytes - 1] < 0) {
XBitNegate(x, XBytes);
Sign = 0x8000;
}
else
Sign = 0;
for(Exponent = 0; Exponent < XBits; Exponent++) {
if(XBitShift(x, XBytes, 1)) {
if(XBytes >= 8) {
XBitShift(x, XBytes, -4);
memcpy(dc, &x[XBytes - 8], 7);
}
else {
memcpy(&dc[7 - XBytes], x, XBytes);
XBitShift(dc, 7, -4);
}
Exponent = 1023 + (IntXBits - Exponent);
di[3] |= (Exponent << 4) | Sign;
}
}
free(x);
return(d);
}
Very nice! Thank you for this wonderful archive. I wonder why I found it only now. Long live the BBS file archives!
This is so awesome! 😀 I’d be cool if you could download an entire archive of this at once, though.
But one thing that puzzles me is the “mtswslnkmcjklsdlsbdmMICROSOFT” string. There is an article about it here. It is definitely worth a read: http://www.os2museum.com/wp/mtswslnk/