diff options
| -rw-r--r-- | src/runtime/print.c | 58 |
1 files changed, 57 insertions, 1 deletions
diff --git a/src/runtime/print.c b/src/runtime/print.c index ebc461bc4..46ecda80d 100644 --- a/src/runtime/print.c +++ b/src/runtime/print.c @@ -49,7 +49,63 @@ sys·printbool(bool v) void sys·printfloat(float64 v) { - sys·write(1, "printfloat", 10); + byte buf[20]; + int32 e, s, i, n; + float64 h; + + n = 5; // digits printed + e = 0; // exp + s = 0; // sign + if(v != 0) { + // sign + if(v < 0) { + v = -v; + s = 1; + } + + // normalize + while(v >= 10) { + e++; + v /= 10; + } + while(v < 1) { + e--; + v *= 10; + } + + // round + h = 5; + for(i=0; i<n; i++) + h /= 10; + v += h; + if(v >= 10) { + e++; + v /= 10; + } + } + + // format +d.dddd+edd + buf[0] = '+'; + if(s) + buf[0] = '-'; + for(i=0; i<n; i++) { + s = v; + buf[i+2] = s+'0'; + v -= s; + v *= 10.; + } + buf[1] = buf[2]; + buf[2] = '.'; + + buf[n+2] = '+'; + if(e < 0) { + e = -e; + buf[n+2] = '-'; + } + buf[n+3] = 'e'; + buf[n+4] = (e/10) + '0'; + buf[n+5] = (e%10) + '0'; + sys·write(1, buf, n+6); } void |