Add memcpy_tointerleaveQuad (thanks Frank)

memcpy_audio.S

 	BX lr
 
 
+
+/* void memcpy_tointerleaveQuad(int16_t *dst, const int16_t *src1, const int16_t *src2, const int16_t *src3, const int16_t *src4) */
+ .global	memcpy_tointerleaveQuad
+.thumb_func
+	memcpy_tointerleaveQuad:
+
+	@ r0: dst
+	@ r1: src1
+	@ r2: src2
+	@ r3: src3
+	@ r4: src4
+
+	push	{r4-r11}
+	ldr r4, [sp, #(0+32)] //4th parameter is saved on the stack
+	add r11,r0,#512		// TODO: 512 = AUDIO_BLOCK_SAMPLES*4
+	.align 2
+.loopQuad:
+
+	.irp offset, 1,2
+
+	ldr r5, [r1],4
+	ldr r6, [r3],4
+	pkhbt r7,r5,r6,LSL #16
+	pkhtb r9,r6,r5,ASR #16
+	ldr r5, [r2],4
+	ldr r6, [r4],4
+	pkhbt r8,r5,r6,LSL #16
+	pkhtb r10,r6,r5,ASR #16
+
+	stmia r0!, {r7-r10}
+
+	.endr
+
+	cmp r11, r0
+	bne .loopQuad
+
+	pop	{r4-r11}
+
+	BX lr
+
+
 .END
 
 #endif

memcpy_audio.h

 void memcpy_tointerleaveLR(int16_t *dst, const int16_t *srcL, const int16_t *srcR);
 void memcpy_tointerleaveL(int16_t *dst, const int16_t *srcL);
 void memcpy_tointerleaveR(int16_t *dst, const int16_t *srcR);
+void memcpy_tointerleaveQuad(int16_t *dst, const int16_t *src1, const int16_t *src2,
+	const int16_t *src3, const int16_t *src4);
 #ifdef __cplusplus
 }
 #endif

output_i2s_quad.cpp

 	src4 = (block_ch4_1st) ? block_ch4_1st->data + ch4_offset : zeros;
 
 	// TODO: fast 4-way interleaved memcpy...
+#if 1
+	memcpy_tointerleaveQuad(dest, src1, src2, src3, src4);
+#else
 	for (int i=0; i < AUDIO_BLOCK_SAMPLES/2; i++) {
 		*dest++ = *src1++;
 		*dest++ = *src3++;
 		*dest++ = *src2++;
 		*dest++ = *src4++;
 	}
+#endif
 
 	if (block_ch1_1st) {
 		if (ch1_offset == 0) {