git.y1.nz

commit c53d99dbc4de00a683a63d529c480172606d9488
parent c5f6be1e644edbf11eebfda08b04c783c4419977
Author: Lior Halphon <LIJI32@gmail.com>
Date:   Sun, 26 Dec 2021 15:20:46 +0200

Abolished slow double use

Diffstat:
M
Core/apu.c
17
+++--------------
M
Core/apu.h
5
+----
M
Core/gb.c
3
---
M
Core/timing.c
2
+-

4 files changed, 5 insertions(+), 22 deletions(-)
diff --git a/Core/apu.c b/Core/apu.c
@@ -765,8 +765,9 @@ void GB_apu_run(GB_gameboy_t *gb)
     if (gb->apu_output.sample_rate) {
         gb->apu_output.cycles_since_render += cycles;
 
-        if (gb->apu_output.sample_cycles >= gb->apu_output.cycles_per_sample) {
-            gb->apu_output.sample_cycles -= gb->apu_output.cycles_per_sample;
+        uint32_t clock_rate = GB_get_clock_rate(gb) * 2;
+        if (gb->apu_output.sample_cycles >= clock_rate) {
+            gb->apu_output.sample_cycles -= clock_rate;
             render(gb);
         }
     }
@@ -1462,8 +1463,6 @@ void GB_set_sample_rate(GB_gameboy_t *gb, unsigned sample_rate)
     if (sample_rate) {
         gb->apu_output.highpass_rate = pow(0.999958,  GB_get_clock_rate(gb) / (double)sample_rate);
     }
-    gb->apu_output.rate_set_in_clocks = false;
-    GB_apu_update_cycles_per_sample(gb);
 }
 
 void GB_set_sample_rate_by_clocks(GB_gameboy_t *gb, double cycles_per_sample)
@@ -1473,10 +1472,8 @@ void GB_set_sample_rate_by_clocks(GB_gameboy_t *gb, double cycles_per_sample)
         GB_set_sample_rate(gb, 0);
         return;
     }
-    gb->apu_output.cycles_per_sample = cycles_per_sample;
     gb->apu_output.sample_rate = GB_get_clock_rate(gb) / cycles_per_sample * 2;
     gb->apu_output.highpass_rate = pow(0.999958, cycles_per_sample);
-    gb->apu_output.rate_set_in_clocks = true;
 }
 
 void GB_apu_set_sample_callback(GB_gameboy_t *gb, GB_sample_callback_t callback)
@@ -1489,14 +1486,6 @@ void GB_set_highpass_filter_mode(GB_gameboy_t *gb, GB_highpass_mode_t mode)
     gb->apu_output.highpass_mode = mode;
 }
 
-void GB_apu_update_cycles_per_sample(GB_gameboy_t *gb)
-{
-    if (gb->apu_output.rate_set_in_clocks) return;
-    if (gb->apu_output.sample_rate) {
-        gb->apu_output.cycles_per_sample = 2 * GB_get_clock_rate(gb) / (double)gb->apu_output.sample_rate; /* 2 * because we use 8MHz units */
-    }
-}
-
 void GB_set_interference_volume(GB_gameboy_t *gb, double volume)
 {
     gb->apu_output.interference_volume = volume;
diff --git a/Core/apu.h b/Core/apu.h
@@ -143,8 +143,7 @@ typedef enum {
 typedef struct {
     unsigned sample_rate;
 
-    double sample_cycles; // In 8 MHz units
-    double cycles_per_sample;
+    unsigned sample_cycles; // Counts by sample_rate until it reaches the clock frequency
 
     // Samples are NOT normalized to MAX_CH_AMP * 4 at this stage!
     unsigned cycles_since_render;
@@ -159,7 +158,6 @@ typedef struct {
     
     GB_sample_callback_t sample_callback;
     
-    bool rate_set_in_clocks;
     double interference_volume;
     double interference_highpass;
 } GB_apu_output_t;
@@ -178,7 +176,6 @@ internal void GB_apu_div_event(GB_gameboy_t *gb);
 internal void GB_apu_div_secondary_event(GB_gameboy_t *gb);
 internal void GB_apu_init(GB_gameboy_t *gb);
 internal void GB_apu_run(GB_gameboy_t *gb);
-internal void GB_apu_update_cycles_per_sample(GB_gameboy_t *gb);
 #endif
 
 #endif /* apu_h */
diff --git a/Core/gb.c b/Core/gb.c
@@ -1653,8 +1653,6 @@ void GB_reset(GB_gameboy_t *gb)
     
     GB_set_internal_div_counter(gb, 8);
 
-    GB_apu_update_cycles_per_sample(gb);
-    
     if (gb->nontrivial_jump_state) {
         free(gb->nontrivial_jump_state);
         gb->nontrivial_jump_state = NULL;
@@ -1758,7 +1756,6 @@ GB_registers_t *GB_get_registers(GB_gameboy_t *gb)
 void GB_set_clock_multiplier(GB_gameboy_t *gb, double multiplier)
 {
     gb->clock_multiplier = multiplier;
-    GB_apu_update_cycles_per_sample(gb);
 }
 
 uint32_t GB_get_clock_rate(GB_gameboy_t *gb)
diff --git a/Core/timing.c b/Core/timing.c
@@ -423,7 +423,7 @@ void GB_advance_cycles(GB_gameboy_t *gb, uint8_t cycles)
         gb->double_speed_alignment += cycles;
     }
     gb->hdma_cycles += cycles;
-    gb->apu_output.sample_cycles += cycles;
+    gb->apu_output.sample_cycles += cycles * gb->apu_output.sample_rate;
     gb->cycles_since_last_sync += cycles;
     gb->cycles_since_run += cycles;
     

This webpage is intended to be an accessible preview of this repository. To get a fuller picture, clone it and use the git CLI.