diff options
| -rw-r--r-- | Makefile | 3 | ||||
| -rw-r--r-- | slowbaud.c | 20 |
2 files changed, 22 insertions, 1 deletions
@@ -16,6 +16,9 @@ $(PROJ).1: $(PROJ).rst README.txt: $(PROJ).1 man ./$(PROJ).1 | sed 's,_\010,,' > README.txt +test: all + sh test.sh + # Don't remove the man page or README here, it's in git. clean: rm -f $(PROJ) core *.o @@ -41,6 +41,13 @@ struct timeval tv; struct itimerval itv, itv_disarm; sigset_t sigmask; +#define FRACTIONAL_USEC + +#ifdef FRACTIONAL_USEC +#define FRAC_US_DENOM 100 +int frac_us_num; +#endif + #define NOW_USEC() ( (gettimeofday(&tv, NULL)), tv.tv_sec * 1000000L + tv.tv_usec ) void die(const char *msg) { @@ -77,6 +84,10 @@ void slow_write(int outfd, char c) { target = NOW_USEC() + interval; +#ifdef FRACTIONAL_USEC + if((random() % FRAC_US_DENOM) < frac_us_num) target++; +#endif + write(outfd, &c, 1); outbytes++; sigwait(&sigmask, &j); @@ -85,7 +96,8 @@ void slow_write(int outfd, char c) { now = NOW_USEC(); if(now > target) { overslept = now - target; - if(overslept < interval) { + if(overslept < itv.it_interval.tv_usec) { + // fprintf(stderr, "overslept %luus\n", overslept); itv.it_interval.tv_usec -= overslept; itv.it_value.tv_usec = itv.it_interval.tv_usec; } @@ -287,6 +299,12 @@ int main(int argc, char **argv) { interval = (unsigned long)(1000000.0L / ((double)bps / 10.0L)); if(debug) fprintf(stderr, "interval %ld us\n", interval); +#ifdef FRACTIONAL_USEC + frac_us_num = (double)FRAC_US_DENOM * ((1000000.0L / ((double)bps / 10.0L) - interval)); + fprintf(stderr, "%d %d\n", interval, frac_us_num); + // srandom(NOW_USEC()); +#endif + if(*argv && argv[0][0] == '-' && argv[0][1] == '-' && !argv[0][2]) { if(debug) fprintf(stderr, "skipping -- argument\n"); argv++, argc--; |