arm7: decompile SND_channel

7 files changed, 131 insertions, 219 deletions

diff --git a/arm7/asm/SND_channel.s b/arm7/asm/SND_channel.s
deleted file mode 100644
index 44744493..00000000
--- a/arm7/asm/SND_channel.s
+++ /dev/null
@@ -1,208 +0,0 @@
-	.include "asm/macros.inc"
-	.include "global.inc"
-
-    .text
-
-	arm_func_start ExChannelLfoUpdate
-ExChannelLfoUpdate: ; 0x037FC530
-	stmdb	sp!, {r4, r5, r6, lr}
-	mov	r6, r0
-	mov	r5, r1
-	add	r0, r6, #40	; 0x28
-	bl	SND_GetLfoValue
-	mov	r4, r0
-	mov	ip, r0, asr #31
-	mov	r3, #0
-	cmp	ip, r3
-	cmpeq	r0, r3
-	beq	_037FC5B0
-	ldrb	r1, [r6, #40]	; 0x28
-	cmp	r1, #0
-	beq	_037FC59C
-	cmp	r1, #1
-	beq	_037FC584
-	cmp	r1, #2
-	moveq	ip, ip, lsl #6
-	orreq	ip, ip, r0, lsr #26
-	moveq	r4, r0, lsl #6
-	b	_037FC5A8
-_037FC584:
-	mov	r2, #60	; 0x3c
-	umull	r4, r1, r0, r2
-	mla	r1, r0, r3, r1
-	mla	r1, ip, r2, r1
-	mov	ip, r1
-	b	_037FC5A8
-_037FC59C:
-	mov	ip, ip, lsl #6
-	orr	ip, ip, r0, lsr #26
-	mov	r4, r0, lsl #6
-_037FC5A8:
-	mov	r4, r4, lsr #14
-	orr	r4, r4, ip, lsl #18
-_037FC5B0:
-	cmp	r5, #0
-	beq	_037FC5C0
-	add	r0, r6, #40	; 0x28
-	bl	SND_UpdateLfo
-_037FC5C0:
-	mov	r0, r4
-	ldmia	sp!, {r4, r5, r6, lr}
-	bx	lr
-
-	arm_func_start ExChannelSweepUpdate
-ExChannelSweepUpdate: ; 0x037FC5CC
-	stmdb	sp!, {r4, r5, lr}
-	sub	sp, sp, #4
-	mov	r4, r0
-	mov	r5, r1
-	ldrsh	r3, [r4, #50]	; 0x32
-	cmp	r3, #0
-	moveq	r0, #0
-	beq	_037FC630
-	ldr	r0, [r4, #20]
-	ldr	r2, [r4, #24]
-	cmp	r0, r2
-	movge	r0, #0
-	bge	_037FC630
-	sub	r0, r2, r0
-	smull	r0, r1, r3, r0
-	mov	r3, r2, asr #31
-	bl	_ll_sdiv
-	cmp	r5, #0
-	beq	_037FC630
-	ldrb	r1, [r4, #3]
-	mov	r1, r1, lsl #29
-	movs	r1, r1, lsr #31
-	ldrne	r1, [r4, #20]
-	addne	r1, r1, #1
-	strne	r1, [r4, #20]
-_037FC630:
-	add	sp, sp, #4
-	ldmia	sp!, {r4, r5, lr}
-	bx	lr
-
-	arm_func_start ExChannelVolumeCmp
-ExChannelVolumeCmp: ; 0x037FC63C
-	stmfd	sp!, {lr}
-	sub	sp, sp, #4
-	ldrh	lr, [r0, #36]	; 0x24
-	and	r2, lr, #255	; 0xff
-	ldrh	ip, [r1, #36]	; 0x24
-	and	r0, ip, #255	; 0xff
-	mov	r2, r2, lsl #4
-	mov	r3, r0, lsl #4
-	ldr	r1, _037FC698	; =sSampleDataShiftTable
-	ldrb	r0, [r1, lr, asr #8]
-	mov	r2, r2, asr r0
-	ldrb	r0, [r1, ip, asr #8]
-	mov	r0, r3, asr r0
-	cmp	r2, r0
-	beq	_037FC688
-	cmp	r2, r0
-	movlt	r0, #1
-	mvnge	r0, #0
-	b	_037FC68C
-_037FC688:
-	mov	r0, #0
-_037FC68C:
-	add	sp, sp, #4
-	ldmia	sp!, {lr}
-	bx	lr
-_037FC698:	.word	sSampleDataShiftTable
-
-	arm_func_start ExChannelStart
-ExChannelStart: ; 0x037FC69C
-	stmdb	sp!, {r4, lr}
-	mov	r4, r0
-	ldr	r0, _037FC6E4	; =0xFFFE9680
-	str	r0, [r4, #16]
-	mov	r0, #0
-	strb	r0, [r4, #2]
-	str	r1, [r4, #52]	; 0x34
-	add	r0, r4, #40	; 0x28
-	bl	SND_StartLfo
-	ldrb	r0, [r4, #3]
-	orr	r0, r0, #2
-	strb	r0, [r4, #3]
-	ldrb	r0, [r4, #3]
-	bic	r0, r0, #1
-	orr	r0, r0, #1
-	strb	r0, [r4, #3]
-	ldmia	sp!, {r4, lr}
-	bx	lr
-_037FC6E4:	.word	0xFFFE9680
-
-	arm_func_start ExChannelSetup
-ExChannelSetup: ; 0x037FC6E8
-	stmdb	sp!, {r4, lr}
-	mov	r4, r0
-	mov	ip, #0
-	str	ip, [r4, #80]	; 0x50
-	str	r1, [r4, #72]	; 0x48
-	str	r2, [r4, #76]	; 0x4c
-	str	ip, [r4, #52]	; 0x34
-	strb	r3, [r4, #34]	; 0x22
-	mov	r1, #127	; 0x7f
-	strh	r1, [r4, #36]	; 0x24
-	ldrb	r2, [r4, #3]
-	bic	r2, r2, #2
-	strb	r2, [r4, #3]
-	ldrb	r2, [r4, #3]
-	orr	r2, r2, #4
-	strb	r2, [r4, #3]
-	mov	r2, #60	; 0x3c
-	strb	r2, [r4, #8]
-	strb	r2, [r4, #5]
-	strb	r1, [r4, #9]
-	strb	ip, [r4, #10]
-	strh	ip, [r4, #12]
-	strh	ip, [r4, #6]
-	strh	ip, [r4, #14]
-	strb	ip, [r4, #11]
-	strb	r1, [r4, #4]
-	strh	ip, [r4, #50]	; 0x32
-	str	ip, [r4, #24]
-	str	ip, [r4, #20]
-	bl	SND_SetExChannelAttack
-	mov	r0, r4
-	mov	r1, #127	; 0x7f
-	bl	SND_SetExChannelDecay
-	mov	r0, r4
-	mov	r1, #127	; 0x7f
-	bl	SND_SetExChannelSustain
-	mov	r0, r4
-	mov	r1, #127	; 0x7f
-	bl	SND_SetExChannelRelease
-	add	r0, r4, #40	; 0x28
-	bl	SND_InitLfoParam
-	ldmia	sp!, {r4, lr}
-	bx	lr
-
-	arm_func_start CalcDecayCoeff
-CalcDecayCoeff: ; 0x037FC794
-	stmfd	sp!, {lr}
-	sub	sp, sp, #4
-	mov	r1, r0
-	cmp	r1, #127	; 0x7f
-	ldreq	r0, _037FC7F0	; =0x0000FFFF
-	beq	_037FC7E4
-	cmp	r1, #126	; 0x7e
-	moveq	r0, #15360	; 0x3c00
-	beq	_037FC7E4
-	cmp	r1, #50	; 0x32
-	movlt	r0, r1, lsl #1
-	addlt	r0, r0, #1
-	movlt	r0, r0, lsl #16
-	movlt	r0, r0, lsr #16
-	blt	_037FC7E4
-	mov	r0, #7680	; 0x1e00
-	rsb	r1, r1, #126	; 0x7e
-	bl	_s32_div_f
-	mov	r0, r0, lsl #16
-	mov	r0, r0, lsr #16
-_037FC7E4:
-	add	sp, sp, #4
-	ldmia	sp!, {lr}
-	bx	lr
-_037FC7F0:	.word	0x0000FFFF
diff --git a/arm7/lib/include/SND_channel.h b/arm7/lib/include/SND_channel.h
index 718e7e2b..ea179968 100644
--- a/arm7/lib/include/SND_channel.h
+++ b/arm7/lib/include/SND_channel.h
@@ -3,6 +3,8 @@
 
 #include "nitro/types.h"
 
+#include "SND_exChannel.h"
+
 void SND_SetupChannelPcm(
     s32 chnIdx,
     const void *data,
@@ -40,6 +42,6 @@ void SND_SetChannelPan(s32 chnIdx, s32 pan);
 void SND_SetChannelTimer(s32 chnIdx, s32 timer);
 
 // TODO move this function to SND_exChannel.c
-u16 CalcDecayCoeff(s32 value);
+u16 CalcDecayCoeff(int value);
 
 #endif //GUARD_SND_CHANNEL_H
diff --git a/arm7/lib/include/SND_exChannel.h b/arm7/lib/include/SND_exChannel.h
index dfd93f21..fcc3a548 100644
--- a/arm7/lib/include/SND_exChannel.h
+++ b/arm7/lib/include/SND_exChannel.h
@@ -6,8 +6,6 @@
 #include "nitro/SND_exChannel_shared.h"
 #include "nitro/SND_main_shared.h"
 
-typedef void (*SNDExChannelCallback)(struct SNDExChannel *chn, s32 status, void *userData);
-
 void SND_ExChannelInit(void);
 void SND_UpdateExChannel(void);
 void SND_ExChannelMain(BOOL step);
@@ -26,10 +24,10 @@ void SND_FreeExChannel(struct SNDExChannel *chn);
 BOOL SND_IsChannelActive(s32 idx);
 
 // TODO internal functions, move these so exChannel
-s32 ExChannelSweepUpdate(struct SNDExChannel *chn, BOOL step);
-s32 ExChannelLfoUpdate(struct SNDExChannel *chn, BOOL step);
-void ExChannelStart(struct SNDExChannel *chn, s32);
-s32 ExChannelVolumeCmp(struct SNDExChannel *chn_a, struct SNDExChannel *chn_b);
-void ExChannelSetup(struct SNDExChannel *, SNDExChannelCallback callback, void *callbackUserData, s32 priority);
+int ExChannelSweepUpdate(struct SNDExChannel *chn, BOOL step);
+int ExChannelLfoUpdate(struct SNDExChannel *chn, BOOL step);
+void ExChannelStart(struct SNDExChannel *chn, int length);
+int ExChannelVolumeCmp(struct SNDExChannel *chn_a, struct SNDExChannel *chn_b);
+void ExChannelSetup(struct SNDExChannel *, SNDExChannelCallback callback, void *callbackUserData, int priority);
 
 #endif //GUARD_SND_EXCHANNEL_H
diff --git a/arm7/lib/include/SND_lfo.h b/arm7/lib/include/SND_lfo.h
index 05d4647e..43055c27 100644
--- a/arm7/lib/include/SND_lfo.h
+++ b/arm7/lib/include/SND_lfo.h
@@ -8,6 +8,6 @@
 void SND_InitLfoParam(struct SNDLfoParam *lfoParam);
 void SND_StartLfo(struct SNDLfo *lfo);
 void SND_UpdateLfo(struct SNDLfo *lfo);
-s32 SND_LfoGetValue(struct SNDLfo *lfo);
+int SND_GetLfoValue(struct SNDLfo *lfo);
 
 #endif //GUARD_SND_LFO_H
diff --git a/arm7/lib/src/SND_channel.c b/arm7/lib/src/SND_channel.c
new file mode 100644
index 00000000..66acf606
--- /dev/null
+++ b/arm7/lib/src/SND_channel.c
@@ -0,0 +1,116 @@
+#include "SND_channel.h"
+
+#include "SND_lfo.h"
+
+// TODO remove this extern once we actually know where this table is
+extern u8 sSampleDataShiftTable[4];
+
+u16 CalcDecayCoeff(int vol) {
+    if (vol == 127)
+        return 0xFFFF;
+    else if (vol == 126)
+        return 0x3C00;
+    else if (vol < 50)
+        return (u16)(vol * 2 + 1);
+    else
+        return (u16)(0x1E00 / (126 - vol));
+}
+
+void ExChannelSetup(struct SNDExChannel *chn, SNDExChannelCallback callback, void *callbackUserData, int priority) {
+    chn->channelLLNext = NULL;
+    chn->callback = callback;
+    chn->callbackUserData = callbackUserData;
+    chn->length = 0;
+    chn->priority = (u8)priority;
+    chn->volume = 127;
+    chn->flags.start = FALSE;
+    chn->flags.autoSweep = TRUE;
+    chn->midiKey = 60;
+    chn->rootMidiKey = 60;
+    chn->velocity = 127;
+    chn->initPan = 0;
+    chn->userDecay = 0;
+    chn->userDecay2 = 0;
+    chn->userPitch = 0;
+    chn->userPan = 0;
+    chn->panRange = 127;
+    chn->sweepPitch = 0;
+    chn->sweepLength = 0;
+    chn->sweepCounter = 0;
+
+    SND_SetExChannelAttack(chn, 127);
+    SND_SetExChannelDecay(chn, 127);
+    SND_SetExChannelSustain(chn, 127);
+    SND_SetExChannelRelease(chn, 127);
+    SND_InitLfoParam(&chn->lfo.param);
+}
+
+void ExChannelStart(struct SNDExChannel *chn, int length) {
+    chn->envAttenuation = -92544;
+    chn->envStatus = 0;
+    chn->length = length;
+    SND_StartLfo(&chn->lfo);
+    chn->flags.start = TRUE;
+    chn->flags.active = TRUE;
+}
+
+int ExChannelVolumeCmp(struct SNDExChannel *chn_a, struct SNDExChannel *chn_b) {
+    int vol_a = chn_a->volume & 0xFF;
+    int vol_b = chn_b->volume & 0xFF;
+
+    vol_a <<= 4;
+    vol_b <<= 4;
+
+    vol_a >>= sSampleDataShiftTable[chn_a->volume >> 8];
+    vol_b >>= sSampleDataShiftTable[chn_b->volume >> 8];
+
+    if (vol_a != vol_b) {
+        if (vol_a < vol_b)
+            return 1;
+        else
+            return -1;
+    }
+    return 0;
+}
+
+int ExChannelSweepUpdate(struct SNDExChannel *chn, BOOL step) {
+    s64 result;
+
+    if (chn->sweepPitch == 0) {
+        result = 0;
+    } else if (chn->sweepCounter >= chn->sweepLength) {
+        result = 0;
+    } else {
+        result = (s64)chn->sweepPitch * (chn->sweepLength - chn->sweepCounter) / chn->sweepLength;
+
+        if (step && chn->flags.autoSweep)
+            chn->sweepCounter++;
+    }
+
+    return (int)result;
+}
+
+int ExChannelLfoUpdate(struct SNDExChannel *chn, BOOL step) {
+    s64 result = SND_GetLfoValue(&chn->lfo);
+
+    if (result != 0) {
+        switch (chn->lfo.param.target) {
+        case SND_LFO_VOLUME:
+            result *= 60;
+            break;
+        case SND_LFO_PITCH:
+            result <<= 6;
+            break;
+        case SND_LFO_PAN:
+            result <<= 6;
+            break;
+        }
+        result >>= 14;
+    }
+
+    if (step) {
+        SND_UpdateLfo(&chn->lfo);
+    }
+
+    return (int)result;
+}
diff --git a/arm7/lib/src/SND_lfo.c b/arm7/lib/src/SND_lfo.c
index eca98197..262c6d27 100644
--- a/arm7/lib/src/SND_lfo.c
+++ b/arm7/lib/src/SND_lfo.c
@@ -32,7 +32,7 @@ void SND_UpdateLfo(struct SNDLfo *lfo) {
     }
 }
 
-s32 SND_GetLfoValue(struct SNDLfo *lfo) {
+int SND_GetLfoValue(struct SNDLfo *lfo) {
     if (lfo->param.depth == 0) {
         return 0;
     } else if (lfo->delayCounter < lfo->param.delay) {
diff --git a/include/nitro/SND_exChannel_shared.h b/include/nitro/SND_exChannel_shared.h
index 386e6ac8..c7743cd6 100644
--- a/include/nitro/SND_exChannel_shared.h
+++ b/include/nitro/SND_exChannel_shared.h
@@ -45,6 +45,10 @@ struct SNDLfo {
     u16 counter;                // 0x8
 }; // size = 0xA
 
+struct SNDExChannel;
+
+typedef void (*SNDExChannelCallback)(struct SNDExChannel *chn, int status, void *userData);
+
 struct SNDExChannel {
     u8 id;              // 0x00
     u8 type;            // 0x01
@@ -95,7 +99,7 @@ struct SNDExChannel {
         s32 dutyCycle;
     };                  // 0x44
 
-    void (*callback)(struct SNDExChannel *chn, u32 status, void *userData); // 0x48
+    SNDExChannelCallback callback; // 0x48
     void *callbackUserData; // 0x4C
 
     struct SNDExChannel *channelLLNext; // 0x50