amalgamation

[picodrive.git] / Pico / cd / pcm.c

diff --git a/Pico/cd/pcm.c b/Pico/cd/pcm.c
index 1de04d6..6ac493a 100644 (file)
--- a/Pico/cd/pcm.c
+++ b/Pico/cd/pcm.c
@@ -1,9 +1,13 @@
+// Emulation routines for the RF5C164 PCM chip.
+// Based on Gens code by Stéphane Dallongeville
+// (c) Copyright 2007, Grazvydas "notaz" Ignotas
+
 #include "../PicoInt.h"
 #include "pcm.h"
 
 static unsigned int g_rate = 0; // 18.14 fixed point
 
-void pcm_write(unsigned int a, unsigned int d)
+PICO_INTERNAL_ASM void pcm_write(unsigned int a, unsigned int d)
 {
 //printf("pcm_write(%i, %02x)\n", a, d);
 
@@ -46,18 +50,17 @@ void pcm_write(unsigned int a, unsigned int d)
 }
 
 
-void pcm_set_rate(int rate)
+PICO_INTERNAL void pcm_set_rate(int rate)
 {
-       double step = 31.8 * 1024.0 / (double) rate; // max <4 @ 8000Hz
+       float step = 31.8 * 1024.0 / (float) rate; // max <4 @ 8000Hz
        step *= 256*256/4;
        g_rate = (unsigned int) step;
-       printf("g_rate: %08x\n", g_rate);
+       if (step - (float) g_rate >= 0.5) g_rate++;
+       printf("g_rate: %f %08x\n", (double)step, g_rate);
 }
 
 
-// TODO: make use of the fact that max_length == 3
-
-void pcm_update(int *buffer, int length, int stereo)
+PICO_INTERNAL void pcm_update(int *buffer, int length, int stereo)
 {
        struct pcm_chan *ch;
        unsigned int step, addr;
@@ -82,7 +85,7 @@ void pcm_update(int *buffer, int length, int stereo)
                mul_l = ((int)ch->regs[0] * (ch->regs[1] & 0xf)) >> (5+1); // (env * pan) >> 5
                mul_r = ((int)ch->regs[0] * (ch->regs[1] >>  4)) >> (5+1);
                step  = ((unsigned int)(*(unsigned short *)&ch->regs[2]) * g_rate) >> 14; // freq step
-//             printf("step=%i, cstep=%i, mul_l=%i, mul_r=%i, ch=%i, addr=%x, en=%02x\n",
+//             fprintf(stderr, "step=%i, cstep=%i, mul_l=%i, mul_r=%i, ch=%i, addr=%x, en=%02x\n",
 //                     *(unsigned short *)&ch->regs[2], step, mul_l, mul_r, i, addr, Pico_mcd->pcm.enabled);
 
                if (!stereo && mul_l < mul_r) mul_l = mul_r;