2 !!DESCRIPTION!! C-Manual Chapter 7.2: Unary Operators
3 !!ORIGIN!! LCC 4.1 Testsuite
4 !!LICENCE!! own, freely distributeable for non-profit. read CPYRIGHT.LCC
10 int cbits; /* No. of bits per char */
12 int sbits; /* short */
14 int ubits; /* unsigned */
15 int fbits; /* float */
16 int dbits; /* double */
18 float fprec; /* Smallest number that can be */
19 float dprec; /* significantly added to 1. */
21 int flgs; /* Print return codes, by section */
22 int flgm; /* Announce machine dependencies */
23 int flgd; /* give explicit diagnostics */
24 int flgl; /* Report local return codes. */
25 int rrc; /* recent return code */
26 int crc; /* Cumulative return code */
27 char rfs[8]; /* Return from section */
31 int ubits; /* unsigned */
32 int fbits; /* float */
33 int dbits; /* double */
35 float fprec; /* Smallest number that can be */
36 float dprec; /* significantly added to 1. */
38 int flgs; /* Print return codes, by section */
39 int flgm; /* Announce machine dependencies */
40 int flgd; /* give explicit diagnostics */
41 int flgl; /* Report local return codes. */
42 int rrc; /* recent return code */
43 int crc; /* Cumulative return code */
44 char rfs[8]; /* Return from section */
48 section s26, which pokes around at the hardware
49 trying to figure out the characteristics of the machine that
50 it is running on, saves information that is subsequently
51 used by sections s626, s72, and s757. If this program is
52 to be broken up into smallish pieces, say for running on
53 a microcomputer, take care to see that s26 is called before
54 calling any of the latter three sections.
58 2.6 Hardware Characteristics
61 #ifndef NO_OLD_FUNC_DECL
66 s26(struct defs *pd0) {
68 static char qs26[8] = "s26 ";
72 float temp, one, delta;
75 static char s[] = "%3d bits in %ss.\n";
76 static char s2[] = "%e is the least number that can be added to 1. (%s).\n";
83 /* Here, we shake the machinery a little to see what falls
84 out. First, we find out how many bits are in a char. */
92 pd0->cbits = pd0->cbits+1;
94 /* That information lets us determine the size of everything else. */
96 pd0->ibits = pd0->cbits * sizeof(int);
97 pd0->sbits = pd0->cbits * sizeof(short);
98 pd0->lbits = pd0->cbits * sizeof(long);
99 pd0->ubits = pd0->cbits * sizeof(unsigned);
101 pd0->fbits = pd0->cbits * sizeof(float);
102 pd0->dbits = pd0->cbits * sizeof(double);
105 /* We have now almost reconstructed the table in section 2.6, the
106 exception being the range of the floating point hardware.
107 Now there are just so many ways to conjure up a floating point
108 representation system that it's damned near impossible to guess
109 what's going on by writing a program to interpret bit patterns.
110 Further, the information isn't all that useful, if we consider
111 the fact that machines that won't handle numbers between 10**30
112 and 10**-30 are very hard to find, and that people playing with
113 numbers outside that range have a lot more to worry about than
114 just the capacity of the characteristic.
116 A much more useful measure is the precision, which can be ex-
117 pressed in terms of the smallest number that can be added to
118 1. without loss of significance. We calculate that here, for
129 pd0->fprec = delta * 4.;
133 while(tempd != oned) {
137 pd0->dprec = delta * 4.;
140 /* Now, if anyone's interested, we publish the results. */
142 #ifndef CQ26_INCLUDED
144 printf(s,pd0->cbits,"char");
145 printf(s,pd0->ibits,"int");
146 printf(s,pd0->sbits,"short");
147 printf(s,pd0->lbits,"long");
148 printf(s,pd0->ubits,"unsigned");
149 printf(s,pd0->fbits,"float");
150 printf(s,pd0->dbits,"double");
152 printf(s2,pd0->fprec,"float");
153 printf(s2,pd0->dprec,"double");
155 printf("NO_FLOATS\n");
159 /* Since we are only exploring and perhaps reporting, but not
160 testing any features, we cannot return an error code. */
165 #ifndef NO_OLD_FUNC_DECL
166 s72(pd0) /* 7.2 Unary operators */
170 int s72(struct defs *pd0){
172 static char s72er[] = "s72,er%d\n";
173 static char qs72[8] = "s72 ";
193 while (*pt++ = *ps++);
195 /* The *, denoting indirection, and the &, denoting a
196 pointer, are duals of each other, and ought to behave as
205 /* The unary minus has the conventional meaning. */
212 /* The negation operator (!) has been thoroughly checked out,
213 perhaps more thoroughly than any of the others. The ~ oper-
214 ator gets us a ones complement. */
217 for(j=0;j<pd0->ibits;j++) k = (k<<1)|1;
223 /* Now we look at the ++ and -- operators, which can be
224 used in either prefix or suffix form. With side
225 effects they're loaded. */
229 if( ++k != 6 || --k != 5
230 || k++ != 5 || k-- != 6
236 /* An expression preceded by the parenthesised name of a
237 data type causes conversion of the value of the expression
238 to the named type. This construction is called a cast.
239 Here, we check to see that all of the possible casts and
240 their simple combinations are accepted by the compiler,
241 and that they all produce a correct result for this sample
257 if( (char)s != 26 || (char)i != 26
258 || (char)l != 26 || (char)u != 26
259 || (char)f != 26 || (char)d != 26 ) lrc = lrc+1;
261 if( (short)c != 26 || (short)i != 26
262 || (short)l != 26 || (short)u != 26
263 || (short)f != 26 || (short)d != 26) lrc = lrc+2;
265 if( (int)c != 26 || (int)s != 26
266 || (int)l != 26 || (int)u != 26
267 || (int)f != 26 || (int)d != 26 ) lrc = lrc+4;
269 if( (long)c != 26 || (long)s != 26
270 || (long)i != 26 || (long)u != 26
271 || (long)f != 26 || (long)d != 26 ) lrc = lrc+8;
273 if( (unsigned)c != 26 || (unsigned)s != 26
274 || (unsigned)i != 26 || (unsigned)l != 26
275 || (unsigned)f != 26 || (unsigned)d != 26 ) lrc = lrc+16;
278 if( (float)c != 26. || (float)s != 26.
279 || (float)i != 26. || (float)l != 26.
280 || (float)u != 26. || (float)d != 26. ) lrc = lrc+32;
282 if( (double)c != 26. || (double)s != 26.
283 || (double)i != 26. || (double)l != 26.
284 || (double)u != 26. || (double)f != 26. ) lrc = lrc+64;
292 /* The sizeof operator has been tested previously. */
297 /*********************************************************************************************
298 the main loop that launches the sections
299 *********************************************************************************************/
301 #ifndef NO_TYPELESS_STRUCT_PTR
302 int section(int j,struct* pd0){
304 int section(int j,void* pd0){
307 case 0: return s26(pd0);
308 case 1: return s72(pd0);
312 #define cq_sections 2
315 C REFERENCE MANUAL (main)
318 #ifndef NO_OLD_FUNC_DECL
324 int main(int n,char **args) {
328 static struct defs d0, *pd0;
330 d0.flgs = 1; /* These flags dictate */
331 d0.flgm = 1; /* the verbosity of */
332 d0.flgd = 1; /* the program. */
337 for (j=0; j<cq_sections; j++) {
338 d0.rrc=section(j,pd0);
339 d0.crc=d0.crc+d0.rrc;
340 if(d0.flgs != 0) printf("Section %s returned %d.\n",d0.rfs,d0.rrc);
343 if(d0.crc == 0) printf("\nNo errors detected.\n");
344 else printf("\nFailed.\n");