Regularize timing code

Provide get_timer_value() and get_timer_freq() and use them.  On Arty,
they use mcycle and the known-fixed core frequency, whereas on HiFive1
they use mtime and the known-fixed mtime frequency.

1 files changed, 2 insertions, 5 deletions

diff --git a/software/dhrystone/dhry_stubs.c b/software/dhrystone/dhry_stubs.c
index d3bd14c..0616f86 100644
--- a/software/dhrystone/dhry_stubs.c
+++ b/software/dhrystone/dhry_stubs.c
@@ -3,16 +3,13 @@
 /* The functions in this file are only meant to support Dhrystone on an
  * embedded RV32 system and are obviously incorrect in general. */
 
-// return the cycle counter as though it were the current time
 long time(void)
 {
-  long t;
-  asm volatile ("csrr %0, mcycle" : "=r" (t));
-  return t / (get_cpu_freq() / 1000);
+  return get_timer_value() / get_timer_freq();
 }
 
 // set the number of dhrystone iterations
 void __wrap_scanf(const char* fmt, int* n)
 {
-  *n = 1500000;
+  *n = 100000000;
 }