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Added strtod.c, use it in atof

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This commit is contained in:
ceriel 1988-08-11 12:49:06 +00:00
parent 2cb7fcf861
commit ebfc4a15a4
3 changed files with 100 additions and 71 deletions
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1
lang/cem/libcc/gen/LIST
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@ -1,6 +1,7 @@
tail_cc.2g.a
abs.c
atof.c
strtod.c
atoi.c
atol.c
bcmp.c

73
lang/cem/libcc/gen/atof.c
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@ -1,81 +1,12 @@
/* $Header$ */
#ifndef NOFLOAT
#include <ctype.h>
extern double ldexp();
extern double strtod();
double
atof(p)
register char *p;
{
register int c;
int exp = 0, sign = 1, expsign = 0;
double fl;
double big = (double)(1L << 30) * (1L << 22);
while (isspace(*p)) p++;
c = *p;
switch (c) {
case '-':
sign = -1;
case '+':
p++;
}
fl = 0.0;
while (isdigit(c = *p++)) {
if (fl < big)
fl = 10.0 * fl + (double)(c - '0');
else
exp++;
}
if (c == '.') {
while (isdigit(c = *p++)) {
if (fl < big) {
fl = 10.0 * fl + (double) (c - '0');
exp--;
}
}
}
if (fl == 0) return 0;
if (c == 'E' || c == 'e') {
int exp1 = 0;
int sign = 1;
switch (*p) {
case '-':
sign = -1;
case '+':
p++;
}
while (isdigit(c = *p++)) {
exp1 = 10 * exp1 + c - '0';
}
exp += sign * exp1;
}
if (exp < 0) {
expsign = 1;
exp = -exp;
}
if (exp != 0) {
int oldexp = exp;
double exp5 = 5.0;
double correction = 1.0;
while (exp) {
if (exp % 2) correction *= exp5;
exp /= 2;
if (exp != 0) exp5 *= exp5;
}
if (expsign) fl = fl / correction;
else fl = fl * correction;
fl = ldexp(fl, expsign ? -oldexp : oldexp);
}
return sign * fl;
return strtod(p, (char **) 0);
}
#endif

97
lang/cem/libcc/gen/strtod.c Normal file
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@ -0,0 +1,97 @@
/* $Header$ */
#ifndef NOFLOAT
#include <ctype.h>
extern double ldexp();
#define MAX (0x7fffffffL/10)
double
strtod(p, pp)
register char *p;
char **pp;
{
register int c;
int exp = 0, sign = 1, expsign = 0;
double fl;
long lowl = 0, highl = 0, pos = 1;
int dotseen = 0;
int digitseen = 0;
if (pp) *pp = p;
while (isspace(*p)) p++;
c = *p;
switch (c) {
case '-':
sign = -1;
case '+':
p++;
}
while (isdigit(c = *p++) || (c == '.' && ! dotseen++)) {
if (c == '.') continue;
digit_seen = 1;
if (highl < MAX) {
highl = (highl << 3) + (highl << 1) + (c - '0');
}
else if (pos < MAX) {
pos = (pos << 3) + (pos << 1);
lowl = (lowl << 3) + (lowl << 1) + (c - '0');
}
else exp++;
if (dotseen) exp--;
}
if (! digit_seen) return 0.0;
fl = highl;
if (pos > 1) {
fl = pos * fl + lowl;
}
if (pp) *pp = p-1;
if (c == 'E' || c == 'e') {
int exp1 = 0;
int sign = 1;
switch (*p) {
case '-':
sign = -1;
case '+':
p++;
}
if (isdigit(c = *p)) {
do {
exp1 = 10 * exp1 + c - '0';
} while (isdigit(c = *++p));
if (pp) *pp = p;
}
exp += sign * exp1;
}
if (fl == 0.0) return 0.0;
if (exp < 0) {
expsign = 1;
exp = -exp;
}
if (exp != 0) {
int oldexp = exp;
double exp5 = 5.0;
double correction = 1.0;
while (exp) {
if (exp % 2) correction *= exp5;
exp /= 2;
if (exp != 0) exp5 *= exp5;
}
if (expsign) fl = fl / correction;
else fl = fl * correction;
fl = ldexp(fl, expsign ? -oldexp : oldexp);
}
return sign * fl;
}
#endif