target/mips: Don't use clock_get_ns() in clock period calculation

Currently the MIPS code uses the old clock_get_ns() API to
calculate a time length in nanoseconds:
 cpu->cp0_count_rate * clock_get_ns(MIPS_CPU(cpu)->clock)

This relies on the clock having a period which is an exact number
of nanoseconds.

Switch to the new clock_ticks_to_ns() function, which does the
multiplication internally at a higher precision.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Luc Michel <luc@lmichel.fr>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20201215150929.30311-3-peter.maydell@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

diff --git a/target/mips/cpu.c b/target/mips/cpu.c
index b2cd69ff7f9a4d6f952020ae65ed2e647ee2c2da..2283214c8798d6e840e1437dad0ccf7282f29223 100644 (file)
--- a/target/mips/cpu.c
+++ b/target/mips/cpu.c
@@ -380,8 +380,8 @@ static void mips_cp0_period_set(MIPSCPU *cpu)
 {
     CPUMIPSState *env = &cpu->env;
 
-    env->cp0_count_ns = cpu->cp0_count_rate
-                        * clock_get_ns(MIPS_CPU(cpu)->clock);
+    env->cp0_count_ns = clock_ticks_to_ns(MIPS_CPU(cpu)->clock,
+                                          cpu->cp0_count_rate);
     assert(env->cp0_count_ns);
 }