arm7: decompile SND_lfo

arm7/asm/SND_lfo.s

@@ -1,77 +0,0 @@
-	.include "asm/macros.inc"
-	.include "global.inc"
-
-    .text
-
-	arm_func_start SND_GetLfoValue
-SND_GetLfoValue: ; 0x037FC7F4
-	stmdb	sp!, {r4, lr}
-	mov	r4, r0
-	ldrb	r0, [r4, #2]
-	cmp	r0, #0
-	moveq	r0, #0
-	beq	_037FC83C
-	ldrh	r1, [r4, #6]
-	ldrh	r0, [r4, #4]
-	cmp	r1, r0
-	movcc	r0, #0
-	bcc	_037FC83C
-	ldrh	r0, [r4, #8]
-	mov	r0, r0, lsr #8
-	bl	SND_SinIdx
-	ldrb	r2, [r4, #3]
-	ldrb	r1, [r4, #2]
-	mul	r0, r1, r0
-	mul	r0, r2, r0
-_037FC83C:
-	ldmia	sp!, {r4, lr}
-	bx	lr
-
-	arm_func_start SND_UpdateLfo
-SND_UpdateLfo: ; 0x037FC844
-	ldrh	r2, [r0, #6]
-	ldrh	r1, [r0, #4]
-	cmp	r2, r1
-	addcc	r1, r2, #1
-	strcch	r1, [r0, #6]
-	bxcc	lr
-	ldrh	r2, [r0, #8]
-	ldrb	r1, [r0, #1]
-	mov	r3, r1, lsl #6
-	add	r1, r2, r1, lsl #6
-	mov	r2, r1, lsr #8
-	b	_037FC878
-_037FC874:
-	sub	r2, r2, #128	; 0x80
-_037FC878:
-	cmp	r2, #128	; 0x80
-	bcs	_037FC874
-	ldrh	r1, [r0, #8]
-	add	r1, r1, r3
-	strh	r1, [r0, #8]
-	ldrh	r1, [r0, #8]
-	and	r1, r1, #255	; 0xff
-	strh	r1, [r0, #8]
-	ldrh	r1, [r0, #8]
-	orr	r1, r1, r2, lsl #8
-	strh	r1, [r0, #8]
-	bx	lr
-
-	arm_func_start SND_StartLfo
-SND_StartLfo: ; 0x037FC8A8
-	mov	r1, #0
-	strh	r1, [r0, #8]
-	strh	r1, [r0, #6]
-	bx	lr
-
-	arm_func_start SND_InitLfoParam
-SND_InitLfoParam: ; 0x037FC8B8
-	mov	r2, #0
-	strb	r2, [r0]
-	strb	r2, [r0, #2]
-	mov	r1, #1
-	strb	r1, [r0, #3]
-	mov	r1, #16
-	strb	r1, [r0, #1]
-	strh	r2, [r0, #4]
-	bx	lr

arm7/lib/include/SND_lfo.h

@@ -0,0 +1,13 @@
+#ifndef GUARD_SND_LFO_H
+#define GUARD_SND_LFO_H
+
+#include "nitro/types.h"
+
+#include "nitro/SND_main_shared.h"
+
+void SND_InitLfoParam(struct SNDLfoParam *lfoParam);
+void SND_StartLfo(struct SNDLfo *lfo);
+void SND_UpdateLfo(struct SNDLfo *lfo);
+s32 SND_LfoGetValue(struct SNDLfo *lfo);
+
+#endif //GUARD_SND_LFO_H

arm7/lib/include/SND_util.h

@@ -5,7 +5,8 @@
 
 #define SND_DECIBEL_SQUARE_TABLE_COUNT 
 
-u32 SND_CalcRandom(void);
+u16 SND_CalcRandom(void);
+s8 SND_SinIdx(s32 index);
 
 u16 SND_CalcChannelVolume(s32 value);
 u16 SND_CalcTimer(s32 timer, s32 pitch);

arm7/lib/src/SND_lfo.c

@@ -0,0 +1,43 @@
+#include "SND_lfo.h"
+
+#include "SND_util.h"
+#include "SND_exChannel.h"
+
+void SND_InitLfoParam(struct SNDLfoParam *lfoParam) {
+    lfoParam->target = SND_LFO_PITCH;
+    lfoParam->depth = 0;
+    lfoParam->range = 1;
+    lfoParam->speed = 16;
+    lfoParam->delay = 0;
+}
+
+void SND_StartLfo(struct SNDLfo *lfo) {
+    lfo->counter = 0;
+    lfo->delayCounter = 0;
+}
+
+void SND_UpdateLfo(struct SNDLfo *lfo) {
+    if (lfo->delayCounter < lfo->param.delay) {
+        lfo->delayCounter++;
+    } else {
+        u32 tmp = lfo->counter;
+        tmp += lfo->param.speed << 6;
+        tmp >>= 8;
+        while (tmp >= 0x80) {
+            tmp -= 0x80;
+        }
+        lfo->counter += lfo->param.speed << 6;
+        lfo->counter &= 0xFF;
+        lfo->counter |= tmp << 8;
+    }
+}
+
+s32 SND_GetLfoValue(struct SNDLfo *lfo) {
+    if (lfo->param.depth == 0) {
+        return 0;
+    } else if (lfo->delayCounter < lfo->param.delay) {
+        return 0;
+    } else {
+        return SND_SinIdx((s32)((u32)lfo->counter >> 8)) * lfo->param.depth * lfo->param.range;
+    }
+}