alex/agb
1
0
Fork 0
mirror of https://github.com/italicsjenga/agb.git synced 2025-01-11 09:31:34 +11:00
Code Issues Packages Projects Releases Wiki Activity

Have the constants only in one place

Browse source
This commit is contained in:
Gwilym Kuiper 2021-10-29 15:44:43 +01:00
parent a514625122
commit 26620e850e
3 changed files with 29 additions and 10 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
agb/crt0.s
View file

@ -64,5 +64,5 @@ b .Initialise_mb
b 1b
.pool
.include "src/sound/mixer/mixer.s"
.include "interrupt_handler.s"
.include "src/sound/mixer/mixer.s"

25
agb/src/sound/mixer/mixer.s
View file

@ -1,4 +1,8 @@
.equ SOUND_BUFFER_SIZE, 176
.section .iwram
.global agb_rs__buffer_size
.balign 4
agb_rs__buffer_size:
.word
agb_arm_func agb_rs__mixer_add
@ Arguments
@ -19,8 +23,8 @@ agb_arm_func agb_rs__mixer_add
modifications_fallback:
orr r7, r7, r3, lsl #16 @ r7 now is the left channel followed by the right channel modifications.
mov r5, #0 @ current index we're reading from
mov r8, #SOUND_BUFFER_SIZE @ the number of steps left
mov r5, #0 @ current index we're reading from
ldr r8, agb_rs__buffer_size @ the number of steps left
1:
@ -62,8 +66,8 @@ same_modification:
lsrs r7, r7, #1
bne 1b
mov r5, #0 @ current index we're reading from
mov r8, #SOUND_BUFFER_SIZE @ the number of steps left
mov r5, #0 @ current index we're reading from
ldr r8, agb_rs__buffer_size @ the number of steps left
.macro mixer_add_loop_simple
add r4, r0, r5, asr #8 @ calculate the address of the next read from the sound buffer
@ -132,7 +136,7 @@ agb_arm_func agb_rs__mixer_add_stereo
str r4, [r1], #4 @ store the new value, and increment the pointer
.endm
mov r8, #SOUND_BUFFER_SIZE
ldr r8, agb_rs__buffer_size
1:
mixer_add_loop_simple_stereo
mixer_add_loop_simple_stereo
@ -159,8 +163,10 @@ agb_arm_func agb_rs__mixer_collapse
@ Arguments:
@ r0 = target buffer (i8)
@ r1 = input buffer (i16) of fixnums with 4 bits of precision (read in sets of i16 in an i32)
push {r4}
mov r2, #SOUND_BUFFER_SIZE @ loop counter
ldr r2, agb_rs__buffer_size @ loop counter
mov r4, r2
1:
@ r12 = *r1; r1++
@ -173,11 +179,12 @@ agb_arm_func agb_rs__mixer_collapse
clamp_s8 r12 @ clamp the audio to 8 bit values
clamp_s8 r3
strb r3, [r0, #SOUND_BUFFER_SIZE] @ *(r0 + SOUND_BUFFER_SIZE) = r3
strb r3, [r0, r4] @ *(r0 + r4 = SOUND_BUFFER_SIZE) = r3
strb r12, [r0], #1 @ *r0 = r12; r0++
subs r2, r2, #1 @ r2 -= 1
bne 1b @ loop if not 0
pop {r4}
bx lr
agb_arm_end agb_rs__mixer_collapse
agb_arm_end agb_rs__mixer_collapse

12
agb/src/sound/mixer/sw_mixer.rs
View file

@ -94,6 +94,16 @@ impl Mixer {
const SOUND_FREQUENCY: i32 = 10512;
const SOUND_BUFFER_SIZE: usize = 176;
fn set_asm_buffer_size() {
extern "C" {
static mut agb_rs__buffer_size: usize;
}
unsafe {
agb_rs__buffer_size = SOUND_BUFFER_SIZE;
}
}
#[repr(C, align(4))]
struct SoundBuffer([i8; SOUND_BUFFER_SIZE * 2]);
@ -106,6 +116,8 @@ struct MixerBuffer {
impl MixerBuffer {
fn new() -> Self {
set_asm_buffer_size();
MixerBuffer {
buffer1: SoundBuffer([0; SOUND_BUFFER_SIZE * 2]),
buffer2: SoundBuffer([0; SOUND_BUFFER_SIZE * 2]),