Annotation of gforth/ecvt.c, revision 1.2
1.1 pazsan 1: #include <math.h>
2:
3: #define MAXCONV 0x40
4: char scratch[MAXCONV];
5:
6: char* ecvt(double x, int len, int* exp, int* sign)
7: {
8: int i, j;
9: double z;
10:
11: if(len > (MAXCONV-1)) len = MAXCONV-1;
12:
13: if(x<0)
14: {
15: *sign = 1;
16: x = -x;
17: }
18: else
19: {
20: *sign = 0;
21: }
22:
23: if(x==0)
24: {
25: *exp=0;
26: return "0";
27: }
28:
29: *exp=(int)floor(log10(x));
30: x = x / pow10((double)*exp);
31:
32: *exp += 1;
33:
34: for(i=0; i < len; i++)
35: {
36: z=floor(x);
37: scratch[i]='0'+(char)((int)z);
38: x = (x-z)*10;
39: }
40:
41: if((x >= 5) && i)
42: {
43: for(j=i-1; j>=0; j--)
44: {
45: if(scratch[j]!='9')
46: {
47: scratch[j]+=1; break;
48: }
49: else
50: {
51: scratch[j]='0';
52: }
53: }
54: if(j==0)
55: {
56: scratch[0]='1';
57: *exp += 1;
58: }
59: }
60:
61: scratch[i]='\0';
62:
63: return scratch;
64: }
65:
66: #ifdef TEST
67: int main(int argc, char ** argv)
68: {
69: int a, b;
70: char * conv=ecvt(PI*1e10,20,&a,&b);
71:
72: printf("ecvt Test: %f -> %s, %d, %d\n",PI,conv,a,b);
73: }
74: #endif
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