Give the same assembly treatment to mono sounds

agb/src/sound/mixer/mixer.s

@@ -1,4 +1,4 @@
-.macro mono_add_fn_loop fn_name:req is_first:req
+.macro mono_add_fn_loop fn_name:req is_first:req is_loop:req
 agb_arm_func \fn_name
     @ Arguments
     @ r0 - pointer to the sample data from the beginning
@@ -26,7 +26,11 @@ agb_arm_func \fn_name
 
 .irp reg, r7,r8,r9,r10
     cmp r4, r5, lsr #8          @ check if we're overflowing
+.ifc \is_loop,true
     suble r5, r5, r3            @ if we are, subtract the overflow amount
+.else
+    ble 2f                      @ if we are, zero the rest of the buffer
+.endif
 
     mov r11, r5, lsr #8         @ calculate the next location to get a value from
     ldrsb r11, [r0, r11]        @ load a single value
@@ -44,6 +48,35 @@ agb_arm_func \fn_name
     subs r2, r2, #4
     bne 1b
 
+.ifc \is_loop,false
+    b 3f
+
+2:
+.ifc \is_first,true             @ zero the rest of the buffer as this sample has ended
+    ands r7, r2, #3
+    sub r2, r2, r7
+    beq 5f
+
+4:
+    mov r8, #0
+4:
+    stmia r1!, {{r8}}
+    subs r7, r7, #1
+    bne 4b
+
+5:
+.irp reg, r7,r8,r9,r10
+    mov \reg, #0
+.endr
+5:
+    stmia r1!, {{r7-r10}}
+    subs r2, r2, #4
+    bne 5b
+.endif
+3:
+.endif
+
+
     mov r0, r5 @ return the playback position
     pop {{r4-r11,lr}}
 
@@ -51,8 +84,10 @@ agb_arm_func \fn_name
 agb_arm_end \fn_name
 .endm
 
-mono_add_fn_loop agb_rs__mixer_add_mono_loop_first true
+mono_add_fn_loop agb_rs__mixer_add_mono_loop_first true true
-mono_add_fn_loop agb_rs__mixer_add_mono_loop false
+mono_add_fn_loop agb_rs__mixer_add_mono_loop false true
+mono_add_fn_loop agb_rs__mixer_add_mono_first true false
+mono_add_fn_loop agb_rs__mixer_add_mono false false
 
 .macro stereo_add_fn fn_name:req is_first:req
 agb_arm_func \fn_name

agb/src/sound/mixer/sw_mixer.rs

@@ -19,6 +19,21 @@ use crate::{
     timer::Timer,
 };
 
+macro_rules! add_mono_fn {
+    ($name:ident) => {
+        fn $name(
+            sample_data: *const u8,
+            sample_buffer: *mut i32,
+            buffer_size: usize,
+            restart_amount: Num<u32, 8>,
+            channel_length: usize,
+            current_pos: Num<u32, 8>,
+            playback_speed: Num<u32, 8>,
+            mul_amount: i32,
+        ) -> Num<u32, 8>;
+    };
+}
+
 // Defined in mixer.s
 extern "C" {
     fn agb_rs__mixer_add_stereo(
@@ -41,27 +56,10 @@ extern "C" {
         num_samples: usize,
     );
 
-    fn agb_rs__mixer_add_mono_loop_first(
+    add_mono_fn!(agb_rs__mixer_add_mono_loop_first);
-        sample_data: *const u8,
+    add_mono_fn!(agb_rs__mixer_add_mono_loop);
-        sample_buffer: *mut i32,
+    add_mono_fn!(agb_rs__mixer_add_mono_first);
-        buffer_size: usize,
+    add_mono_fn!(agb_rs__mixer_add_mono);
-        restart_amount: Num<u32, 8>,
-        channel_length: usize,
-        current_pos: Num<u32, 8>,
-        playback_speed: Num<u32, 8>,
-        mul_amount: i32,
-    ) -> Num<u32, 8>;
-
-    fn agb_rs__mixer_add_mono_loop(
-        sample_data: *const u8,
-        sample_buffer: *mut i32,
-        buffer_size: usize,
-        restart_amount: Num<u32, 8>,
-        channel_length: usize,
-        current_pos: Num<u32, 8>,
-        playback_speed: Num<u32, 8>,
-        mul_amount: i32,
-    ) -> Num<u32, 8>;
 }
 
 /// The main software mixer struct.
@@ -518,9 +516,10 @@ impl MixerBuffer {
         let mul_amount =
             ((left_amount.to_raw() as i32) << 16) | (right_amount.to_raw() as i32 & 0x0000ffff);
 
-        if IS_FIRST && channel.should_loop {
+        macro_rules! call_mono_fn {
+            ($fn_name:ident) => {
                 channel.pos = unsafe {
-                agb_rs__mixer_add_mono_loop_first(
+                    $fn_name(
                         channel.data.as_ptr(),
                         working_buffer_i32.as_mut_ptr(),
                         working_buffer_i32.len(),
@@ -530,44 +529,20 @@ impl MixerBuffer {
                         channel.playback_speed,
                         mul_amount,
                     )
-            };
-        } else if !IS_FIRST && channel.should_loop {
-            channel.pos = unsafe {
-                agb_rs__mixer_add_mono_loop(
-                    channel.data.as_ptr(),
-                    working_buffer_i32.as_mut_ptr(),
-                    working_buffer_i32.len(),
-                    channel_len - channel.restart_point,
-                    channel.data.len(),
-                    channel.pos,
-                    channel.playback_speed,
-                    mul_amount,
-                )
-            };
-        } else {
-            for i in 0..self.frequency.buffer_size() {
-                if channel.pos >= channel_len {
-                    channel.is_done = true;
-
-                    break;
                 }
-
-                // SAFETY: channel.pos < channel_len by the above if statement and the fact we reduce the playback speed
-                let value = unsafe { *channel.data.get_unchecked(channel.pos.floor() as usize) }
-                    as i8 as i32;
-
-                // SAFETY: working buffer length = self.frequency.buffer_size()
-                if IS_FIRST {
-                    unsafe {
-                        *working_buffer_i32.get_unchecked_mut(i) = value.wrapping_mul(mul_amount);
-                    }
-                } else {
-                    unsafe {
-                        let value_ref = working_buffer_i32.get_unchecked_mut(i);
-                        *value_ref = value_ref.wrapping_add(value.wrapping_mul(mul_amount));
             };
         }
-                channel.pos += playback_speed;
+
+        match (IS_FIRST, channel.should_loop) {
+            (true, true) => call_mono_fn!(agb_rs__mixer_add_mono_loop_first),
+            (false, true) => call_mono_fn!(agb_rs__mixer_add_mono_loop),
+            (true, false) => {
+                call_mono_fn!(agb_rs__mixer_add_mono_first);
+                channel.is_done = channel.pos > channel_len;
+            }
+            (false, false) => {
+                call_mono_fn!(agb_rs__mixer_add_mono);
+                channel.is_done = channel.pos > channel_len;
             }
         }
     }