Annotation of gforth/ecvt.c, revision 1.4
1.4 ! pazsan 1: /* cheap ecvt replacement */
! 2:
1.1 pazsan 3: #include <math.h>
4:
5: #define MAXCONV 0x40
6: char scratch[MAXCONV];
7:
8: char* ecvt(double x, int len, int* exp, int* sign)
9: {
10: int i, j;
11: double z;
12:
13: if(len > (MAXCONV-1)) len = MAXCONV-1;
14:
15: if(x<0)
16: {
17: *sign = 1;
18: x = -x;
19: }
20: else
21: {
22: *sign = 0;
23: }
1.3 pazsan 24:
1.1 pazsan 25: if(x==0)
1.3 pazsan 26: *exp=-1;
27: else
28: *exp=(int)floor(log10(x));
1.1 pazsan 29: x = x / pow10((double)*exp);
30:
31: *exp += 1;
32:
33: for(i=0; i < len; i++)
34: {
35: z=floor(x);
36: scratch[i]='0'+(char)((int)z);
37: x = (x-z)*10;
38: }
39:
40: if((x >= 5) && i)
41: {
42: for(j=i-1; j>=0; j--)
43: {
44: if(scratch[j]!='9')
45: {
46: scratch[j]+=1; break;
47: }
48: else
49: {
50: scratch[j]='0';
51: }
52: }
53: if(j==0)
54: {
55: scratch[0]='1';
56: *exp += 1;
57: }
58: }
59:
60: scratch[i]='\0';
61:
62: return scratch;
63: }
64:
65: #ifdef TEST
66: int main(int argc, char ** argv)
67: {
68: int a, b;
69: char * conv=ecvt(PI*1e10,20,&a,&b);
70:
71: printf("ecvt Test: %f -> %s, %d, %d\n",PI,conv,a,b);
72: }
73: #endif
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