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include s26 to get bitsize of char

This commit is contained in:
mrdudz 2014-11-22 16:45:23 +01:00
parent f82343c484
commit d712abfe27

View File

@ -4,6 +4,8 @@
!!LICENCE!! own, freely distributeable for non-profit. read CPYRIGHT.LCC
*/
#include "common.h"
struct defs {
int cbits; /* No. of bits per char */
int ibits; /* int */
@ -41,7 +43,124 @@ struct defs {
int crc; /* Cumulative return code */
char rfs[8]; /* Return from section */
/*#include "cq26.c"*/ /* hardware check */
#define CQ26_INCLUDED
/*
section s26, which pokes around at the hardware
trying to figure out the characteristics of the machine that
it is running on, saves information that is subsequently
used by sections s626, s72, and s757. If this program is
to be broken up into smallish pieces, say for running on
a microcomputer, take care to see that s26 is called before
calling any of the latter three sections.
*/
/*
2.6 Hardware Characteristics
*/
#ifndef NO_OLD_FUNC_DECL
s26(pd0)
struct defs *pd0;
{
#else
s26(struct defs *pd0) {
#endif
static char qs26[8] = "s26 ";
char *ps, *pt;
char c0, c1;
#ifndef NO_FLOATS
float temp, one, delta;
double tempd, oned;
#endif
static char s[] = "%3d bits in %ss.\n";
static char s2[] = "%e is the least number that can be added to 1. (%s).\n";
ps = qs26;
pt = pd0->rfs;
while(*pt++ = *ps++);
/* Here, we shake the machinery a little to see what falls
out. First, we find out how many bits are in a char. */
pd0->cbits = 0;
c0 = 0;
c1 = 1;
while(c0 != c1) {
c1 = c1<<1;
pd0->cbits = pd0->cbits+1;
}
/* That information lets us determine the size of everything else. */
pd0->ibits = pd0->cbits * sizeof(int);
pd0->sbits = pd0->cbits * sizeof(short);
pd0->lbits = pd0->cbits * sizeof(long);
pd0->ubits = pd0->cbits * sizeof(unsigned);
#ifndef NO_FLOATS
pd0->fbits = pd0->cbits * sizeof(float);
pd0->dbits = pd0->cbits * sizeof(double);
#endif
/* We have now almost reconstructed the table in section 2.6, the
exception being the range of the floating point hardware.
Now there are just so many ways to conjure up a floating point
representation system that it's damned near impossible to guess
what's going on by writing a program to interpret bit patterns.
Further, the information isn't all that useful, if we consider
the fact that machines that won't handle numbers between 10**30
and 10**-30 are very hard to find, and that people playing with
numbers outside that range have a lot more to worry about than
just the capacity of the characteristic.
A much more useful measure is the precision, which can be ex-
pressed in terms of the smallest number that can be added to
1. without loss of significance. We calculate that here, for
float and double. */
#ifndef NO_FLOATS
one = 1.;
delta = 1.;
temp = 0.;
while(temp != one) {
temp = one+delta;
delta = delta/2.;
}
pd0->fprec = delta * 4.;
oned = 1.;
delta = 1.;
tempd = 0.;
while(tempd != oned) {
tempd = oned+delta;
delta = delta/2.;
}
pd0->dprec = delta * 4.;
#endif
/* Now, if anyone's interested, we publish the results. */
#ifndef CQ26_INCLUDED
if(pd0->flgm != 0) {
printf(s,pd0->cbits,"char");
printf(s,pd0->ibits,"int");
printf(s,pd0->sbits,"short");
printf(s,pd0->lbits,"long");
printf(s,pd0->ubits,"unsigned");
printf(s,pd0->fbits,"float");
printf(s,pd0->dbits,"double");
#ifndef NO_FLOATS
printf(s2,pd0->fprec,"float");
printf(s2,pd0->dprec,"double");
#else
printf("NO_FLOATS\n");
#endif
}
#endif
/* Since we are only exploring and perhaps reporting, but not
testing any features, we cannot return an error code. */
return 0;
}
int extvar;
@ -125,10 +244,13 @@ implementation */
target = ~0U;
mask = 1;
printf("sizeof target: %08x pd0->cbits: %08x\n", sizeof target, pd0->cbits);
printf("mask: %08x target: %08x\n", mask, target);
for(j=0; j<(sizeof target)*pd0->cbits; j++){
mask = mask&target;
target = target>>1;
printf("mask: %08x target: %08x\n", mask, target);
}
if(mask != 1 || target != 0){
@ -200,11 +322,12 @@ setev(){
int section(int j,void* pd0){
#endif
switch(j){
case 0: return s4(pd0);
case 0: return s26(pd0);
case 1: return s4(pd0);
}
}
#define cq_sections 1
#define cq_sections 2
/*
C REFERENCE MANUAL (main)