From d576bbca55613cd442a36e285adec1d88abf38b9 Mon Sep 17 00:00:00 2001
From: Samuel Walker <swalker@piwalker.net>
Date: Wed, 5 Feb 2025 15:49:53 -0700
Subject: [PATCH] passing audio test 4

---
 include/audio.h |   3 ++
 lib/audio.c     | 125 +++++++++++++++++++++++++++++++++---------------
 2 files changed, 90 insertions(+), 38 deletions(-)

diff --git a/include/audio.h b/include/audio.h
index 2625ada..a99a309 100644
--- a/include/audio.h
+++ b/include/audio.h
@@ -20,6 +20,9 @@ typedef struct {
     bool ch4_dac;
 
     bool ch1_len_fz;
+    bool ch2_len_fz;
+    bool ch3_len_fz;
+    bool ch4_len_fz;
 
     u8 volume_left;
     u8 volume_right;
diff --git a/lib/audio.c b/lib/audio.c
index 75d0198..23f0a9b 100644
--- a/lib/audio.c
+++ b/lib/audio.c
@@ -182,8 +182,8 @@ static int audio_callback(const void* input_uffer, void *output_buffer,
         if(dacs) {
             left_out = left - left_cap;
             right_out = right - right_cap;
-            left_cap = left - left_out * 0.996;
-            right_cap = right - right_out * 0.996;
+            left_cap = left - left_out * 0.996f;
+            right_cap = right - right_out * 0.996f;
         }
 
         *out++ = left_out;
@@ -278,7 +278,7 @@ void sq1_sweep() {
     step = ctx.sq1_sweep_direction ? -step : step;
     ctx.sq1_calc_period = ctx.sq1_sweep_period + step;
     //overflow check
-    if(ctx.sq1_calc_period > 0x7FFF) {
+    if(ctx.sq1_calc_period > 0x7FF) {
         ctx.sq1_enable = false;
     }
 }
@@ -304,6 +304,7 @@ void audio_tick(){
             if(ctx.sq2_len >= 64) {
                 ctx.sq2_len = 0;
                 ctx.sq2_enable = false;
+                ctx.ch2_len_fz = true;
             }
         }
 
@@ -311,6 +312,7 @@ void audio_tick(){
             ctx.ch3_len++;
             if(ctx.ch3_len == 0) {
                 ctx.ch3_enable = false;
+                ctx.ch3_len_fz = true;
             }
         }
 
@@ -319,11 +321,12 @@ void audio_tick(){
             if(ctx.ch4_len >= 64) {
                 ctx.ch4_len = 0;
                 ctx.ch4_enable = false;
+                ctx.ch4_len_fz = true;
             }
         }
     }
 
-    if((prev_ticks & (1 << 3)) && !(ticks & (1 << 3))) {
+    if((prev_ticks & (1 << 2)) && !(ticks & (1 << 2))) {
         if(ctx.sq1_env_pace != 0){
             ctx.sq1_env_timer++;
             if(ctx.sq1_env_timer >= ctx.sq1_env_pace) {
@@ -370,17 +373,17 @@ void audio_tick(){
 
     }
 
-    if((prev_ticks & (1 << 2)) && !(ticks & (1 << 2))) {
+    if((prev_ticks & (1 << 1)) && !(ticks & (1 << 1))) {
         ctx.sq1_sweep_timer++;
         if(ctx.sq1_sweep_timer >= ctx.sq1_sweep_pace) {
             ctx.sq1_sweep_timer = 0;
-            if(ctx.sq1_enable && ctx.sq1_sweep_pace){
+            if(ctx.sq1_enable && ctx.sq1_sweep_pace > 0 && ctx.sq1_sweep_enabled){
                 sq1_sweep();
-                if(ctx.sq1_calc_period <= 0x7FFF && ctx.sq1_sweep_step != 0) {
+                if(ctx.sq1_calc_period <= 0x7FF && ctx.sq1_sweep_step != 0) {
                     ctx.sq1_sweep_period = ctx.sq1_calc_period;
                     ctx.sq1_period_reset = ctx.sq1_calc_period;
+                    sq1_sweep();
                 }
-                sq1_sweep();
             }
         }
     }
@@ -396,8 +399,8 @@ void enable_square1() {
     ctx.sq1_sweep_timer = 0;
     ctx.sq1_env_direction = ctx.sq1_env_direction_buffer;
     ctx.sq1_env_pace = ctx.sq1_env_pace_buffer;
-    ctx.sq1_sweep_enabled = (ctx.sq1_sweep_pace || ctx.sq1_sweep_step);
-    if(ctx.sq1_sweep_step) {
+    ctx.sq1_sweep_enabled = ((ctx.sq1_sweep_pace != 0) || (ctx.sq1_sweep_step != 0));
+    if(ctx.sq1_sweep_step != 0) {
         sq1_sweep();
     }
 }
@@ -407,9 +410,6 @@ void enable_square2() {
         return;
     }
     ctx.sq2_enable = true;
-    if(ctx.sq2_len >= 64) {
-        ctx.sq2_len = 0;
-    }
     ctx.sq2_volume = ctx.sq2_initial_volume;
     ctx.sq2_env_timer = 0;
     ctx.sq2_sample = 0;
@@ -423,13 +423,9 @@ void enable_wave() {
         return;
     }
     ctx.ch3_enable = true;
-    if(ctx.ch3_len == 255) {
-        ctx.ch3_len = 0;
-    }
     ctx.ch3_sample = 0;
     ctx.ch3_volume = ctx.ch3_initial_volume;
     ctx.ch3_period_timer = ctx.ch3_period_reset;
-    printf("channel 3 enabled\n");
 }
 
 void enable_noise() {
@@ -437,9 +433,6 @@ void enable_noise() {
         return;
     }
     ctx.ch4_enable = true;
-    if(ctx.ch4_len >= 64) {
-        ctx.ch4_len = 0;
-    }
     ctx.ch4_env_timer = 0;
     ctx.ch4_env_direction = ctx.ch4_env_direction_buffer;
     ctx.ch4_env_pace = ctx.ch4_env_pace_buffer;
@@ -454,7 +447,7 @@ u8 audio_read(u16 address) {
         return value | 0b01110000;
     }
     if(address == 0xFF25) {
-        u8 value;
+        u8 value = 0x0;
         value |= ctx.ch4_left << 7;
         value |= ctx.ch3_left << 6;
         value |= ctx.ch2_left << 5;
@@ -464,6 +457,7 @@ u8 audio_read(u16 address) {
         value |= ctx.ch3_right << 2;
         value |= ctx.ch2_right << 1;
         value |= ctx.ch1_right;
+        //printf("read at %02X; Value: %02X\n", address, value);
         return value;
     }
 
@@ -568,14 +562,14 @@ void reset_buffers(){
     ctx.ch1_dac = 0;
     ctx.ch2_dac = 0;
     ctx.ch3_dac = 0;
-    ctx.ch1_left = 0;
-    ctx.ch1_right = 0;
-    ctx.ch2_left = 0;
-    ctx.ch2_right = 0;
-    ctx.ch3_left = 0;
-    ctx.ch3_right = 0;
-    ctx.ch4_left = 0;
-    ctx.ch4_right = 0;
+    ctx.ch1_left = false;
+    ctx.ch1_right = false;
+    ctx.ch2_left = false;
+    ctx.ch2_right = false;
+    ctx.ch3_left = false;
+    ctx.ch3_right = false;
+    ctx.ch4_left = false;
+    ctx.ch4_right = false;
     ctx.volume_left = 0;
     ctx.volume_right = 0;
     ctx.vin_left = 0;
@@ -651,8 +645,9 @@ void audio_write(u16 address, u8 value){
     }
 
     if(address == 0xFF26) {
-        ctx.audio_enabled = value & 0x80;
+        ctx.audio_enabled = (value & 0x80) == 0x80;
         if(!ctx.audio_enabled) {
+            //printf("audio disabled\n");
             reset_buffers();
         }
     }
@@ -671,6 +666,7 @@ void audio_write(u16 address, u8 value){
         ctx.ch3_right = value & 0b00000100;
         ctx.ch2_right = value & 0b00000010;
         ctx.ch1_right = value & 0b00000001;
+        //printf("write at %02X; Value: %02X\n", address, value);
     }
 
     if(address == 0xFF24) {
@@ -691,8 +687,7 @@ void audio_write(u16 address, u8 value){
         ctx.sq1_duty = value >> 6;
         ctx.sq1_initial_len = value & 0x3F;
         ctx.sq1_len = ctx.sq1_initial_len;
-        static bool unfreeze;
-        unfreeze = true;
+        ctx.ch1_len_fz = false;
         //printf("initial len: %02X\n", ctx.sq1_initial_len);
     }
     if(address == 0xFF12) {
@@ -729,7 +724,6 @@ void audio_write(u16 address, u8 value){
                 ctx.sq1_len++;
             }
         }
-        printf("Value: %02X\n", value);
         ctx.sq1_len_enable = len_en;
         if(value & 0x80) {
             enable_square1();
@@ -741,6 +735,7 @@ void audio_write(u16 address, u8 value){
         ctx.sq2_duty = value >> 6;
         ctx.sq2_initial_len = value & 0x3F;
         ctx.sq2_len = ctx.sq2_initial_len;
+        ctx.ch2_len_fz = false;
     }
     if(address == 0xFF17) {
         ctx.sq2_initial_volume = (value >> 4) & 0x0F;
@@ -759,9 +754,27 @@ void audio_write(u16 address, u8 value){
         //printf("period: %03X, old_period: %03X\n", ctx.sq2_period_reset, prev_period);
     }
     if(address == 0xFF19) {
+        if(ctx.sq2_len == 64) {
+            ctx.sq2_len = 0;
+        }
         ctx.sq2_period_reset = (ctx.sq2_period_reset & 0x0FF) | ((value & 0b111) << 8);
-        ctx.sq2_len_enable = (value & 0x40) == 0x40;
-        if((value & 0x80) == 0x80) {
+        bool len_en = (value & 0x40) == 0x40;
+        if((ticks % 2) == 0 && !ctx.ch2_len_fz && !ctx.sq2_len_enable && len_en){
+            ctx.sq2_len++;
+            if(ctx.sq2_len >= 64) {
+                ctx.sq2_len = 0;
+                ctx.sq2_enable = false;
+                ctx.ch2_len_fz = true;
+            }
+        } 
+        if((ticks % 2) == 0 && ctx.ch2_len_fz && (value & 0x80) == 0x80){
+            ctx.ch2_len_fz = false;
+            if(len_en){
+                ctx.sq2_len++;
+            }
+        }
+        ctx.sq2_len_enable = len_en;
+        if(value & 0x80) {
             enable_square2();
         }
     }
@@ -776,6 +789,7 @@ void audio_write(u16 address, u8 value){
     if(address == 0xFF1B) {
         ctx.ch3_initial_len = value;
         ctx.ch3_len = ctx.ch3_initial_len;
+        ctx.ch3_len_fz = false;
     }
 
     if(address == 0xFF1C) {
@@ -788,7 +802,23 @@ void audio_write(u16 address, u8 value){
 
     if(address == 0xFF1E) {
         ctx.ch3_period_reset = (ctx.ch3_period_reset & 0x0FF) | ((value & 0b111) << 8);
-        ctx.ch3_len_enable = (value & 0x40) == 0x40;
+        bool len_en = (value & 0x40) == 0x40;
+        if((ticks % 2) == 0 && !ctx.ch3_len_fz && !ctx.ch3_len_enable && len_en){
+            if(ctx.ch3_len >= 255) {
+                ctx.ch3_len = 0;
+                ctx.ch3_enable = false;
+                ctx.ch3_len_fz = true;
+            } else {
+                ctx.ch3_len++;
+            }
+        } 
+        if((ticks % 2) == 0 && ctx.ch3_len_fz && (value & 0x80) == 0x80){
+            ctx.ch3_len_fz = false;
+            if(len_en){
+                ctx.ch3_len++;
+            }
+        }
+        ctx.ch3_len_enable = len_en;
         if(value & 0x80) {
             enable_wave();
         }
@@ -797,6 +827,7 @@ void audio_write(u16 address, u8 value){
     if(address == 0xFF20) {
         ctx.ch4_initial_len = value & 0b111111;
         ctx.ch4_len = ctx.ch4_initial_len;
+        ctx.ch4_len_fz = false;
     }
 
     if(address == 0xFF21) {
@@ -821,8 +852,26 @@ void audio_write(u16 address, u8 value){
     }
 
     if(address == 0xFF23) {
-        ctx.ch4_len_enable = (value & 0x40) == 0x40;
-        if((value & 0x80) == 0x80) {
+        if(ctx.ch4_len == 64) {
+            ctx.ch4_len = 0;
+        }
+        bool len_en = (value & 0x40) == 0x40;
+        if((ticks % 2) == 0 && !ctx.ch4_len_fz && !ctx.ch4_len_enable && len_en){
+            ctx.ch4_len++;
+            if(ctx.ch4_len >= 64) {
+                ctx.ch4_len = 0;
+                ctx.ch4_enable = false;
+                ctx.ch4_len_fz = true;
+            }
+        } 
+        if((ticks % 2) == 0 && ctx.ch4_len_fz && (value & 0x80) == 0x80){
+            ctx.ch4_len_fz = false;
+            if(len_en){
+                ctx.ch4_len++;
+            }
+        }
+        ctx.ch4_len_enable = len_en;
+        if(value & 0x80) {
             enable_noise();
         }
     }