https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65668
Bug ID: 65668
Summary: gcc does not know how to use __eabi_uldivmod properly
Product: gcc
Version: 4.9.2
URL: https://gist.github.com/mrvn/0c79b146f74c28da401f
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: goswin-v-b at web dot de
Build: arm-none-eabi
I have a uint64_t free running counter with a frequenzy of 1Mhz and I want to
print that as hours, minutes, seconds and fraction:
volatile uint64_t count = 0x0000000062a54bc4 // for example
uint64_t t = count;
uint32_t frac, seconds, minutes, hours;
frac = t % 1000000;
t /= 1000000;
seconds = t % 60;
t /= 60;
minutes = t % 60;
t /= 60;
hours = t;
This results in 6 calls to __eabi_uldivmod, one for every modulo and every
division, instead of just 3 calls. With long division being rather expensive
that is a substantial waste of time.
