1 files changed, 23 insertions, 6 deletions
diff --git a/test/test_perfmon_cpu.c b/test/test_perfmon_cpu.c
index 8ecb241..6f1414c 100644
--- a/test/test_perfmon_cpu.c
+++ b/test/test_perfmon_cpu.c
@@ -49,17 +49,30 @@ test_report_event(const struct perfmon_event *event, const char *name)
     printf("test: %s: %llu\n", name, count);
 }
 
+static uint64_t
+test_get_pre_overflow_value(uint64_t value)
+{
+    uint64_t pmc_max;
+    unsigned int pmc_width;
+
+    pmc_width = perfmon_get_pmc_width();
+    pmc_max = (1ULL << pmc_width) - 1;
+    pmc_max &= 0xffffffff80000000;
+
+    /* XXX: workaround most processor not allowing full width writes */
+    return ((~value + 1) & 0x7fffffff) | pmc_max;
+}
+
 static void
 test_run(void *arg)
 {
     struct perfmon_event *ev_cycle, *ev_instruction;
     struct perfmon_group *group;
     int error;
-    uint64_t pmc_max;
+    uint64_t value;
 
     (void)arg;
 
-    pmc_max = (1 << perfmon_get_pmc_width()) - 1;
     error = perfmon_group_create(&group);
     error_check(error, "perfmon_group_create");
 
@@ -86,10 +99,14 @@ test_run(void *arg)
     test_report_event(ev_instruction, "instruction");
 
     printf("checking with overflow ...\n");
-    /* TODO: choose value depending of architecture */
-    perfmon_event_write(ev_cycle, pmc_max - perfmon_event_read(ev_cycle) / 2);
-    perfmon_event_write(ev_instruction,
-                        pmc_max - perfmon_event_read(ev_instruction) / 3);
+    value = test_get_pre_overflow_value( perfmon_event_read(ev_cycle) / 2);
+    error = perfmon_event_write(ev_cycle, value);
+    error_check(error, "perfmon_event_write");
+
+    value = test_get_pre_overflow_value(perfmon_event_read(ev_instruction) / 3);
+    error = perfmon_event_write(ev_instruction, value);
+    error_check(error, "perfmon_event_write");
+
     perfmon_event_reset(ev_cycle);
     perfmon_event_reset(ev_instruction);