Use fractional cycles within Lightrec

Instead of computing cycles back and forth between PCSX and Lightrec,
compute and use a cycles-per-opcode value in 22.10 format and use that.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>

diff --git a/libpcsxcore/lightrec/plugin.c b/libpcsxcore/lightrec/plugin.c
index ff74352..2a46942 100644 (file)
--- a/libpcsxcore/lightrec/plugin.c
+++ b/libpcsxcore/lightrec/plugin.c
@@ -64,8 +64,6 @@ static char *name = "retroarch.exe";
 static bool use_lightrec_interpreter;
 static bool use_pcsx_interpreter;
 static bool block_stepping;
-static u32 cycle_mult_to_pcsx; // 22.10 fractional
-static u32 cycle_mult_from_pcsx;
 
 enum my_cp2_opcodes {
        OP_CP2_RTPS             = 0x01,
@@ -144,15 +142,9 @@ static bool has_interrupt(void)
                (regs->cp0[12] & regs->cp0[13] & 0x0300);
 }
 
-static u32 cycles_pcsx_to_lightrec(u32 c)
-{
-       assert((u64)c * cycle_mult_from_pcsx <= (u32)-1);
-       return c * cycle_mult_from_pcsx >> 10;
-}
-
 static void lightrec_tansition_to_pcsx(struct lightrec_state *state)
 {
-       psxRegs.cycle += lightrec_current_cycle_count(state) * cycle_mult_to_pcsx >> 10;
+       psxRegs.cycle += lightrec_current_cycle_count(state) / 1024;
        lightrec_reset_cycle_count(state, 0);
 }
 
@@ -163,8 +155,7 @@ static void lightrec_tansition_from_pcsx(struct lightrec_state *state)
        if (block_stepping || cycles_left <= 0 || has_interrupt())
                lightrec_set_exit_flags(state, LIGHTREC_EXIT_CHECK_INTERRUPT);
        else {
-               lightrec_set_target_cycle_count(state,
-                       cycles_pcsx_to_lightrec(cycles_left));
+               lightrec_set_target_cycle_count(state, cycles_left * 1024);
        }
 }
 
@@ -506,7 +497,7 @@ static void lightrec_plugin_execute_internal(bool block_only)
        if (use_pcsx_interpreter) {
                intExecuteBlock(0);
        } else {
-               u32 cycles_lightrec = cycles_pcsx_to_lightrec(cycles_pcsx);
+               u32 cycles_lightrec = cycles_pcsx * 1024;
                if (unlikely(use_lightrec_interpreter)) {
                        psxRegs.pc = lightrec_run_interpreter(lightrec_state,
                                                              psxRegs.pc,
@@ -584,8 +575,8 @@ static void lightrec_plugin_apply_config()
        u32 cycle_mult = Config.cycle_multiplier_override && Config.cycle_multiplier == CYCLE_MULT_DEFAULT
                ? Config.cycle_multiplier_override : Config.cycle_multiplier;
        assert(cycle_mult);
-       cycle_mult_to_pcsx = (cycle_mult * 1024 + 199) / 200;
-       cycle_mult_from_pcsx = (200 * 1024 + cycle_mult/2) / cycle_mult;
+
+       lightrec_set_cycles_per_opcode(lightrec_state, cycle_mult * 1024 / 100);
 }
 
 static void lightrec_plugin_shutdown(void)