port: restart currently playing MP3 when needed

there's probably a way to determine reset condition without adding an extra field to g_Mp3Vars, but I can't be arsed to figure it out

port/include/mixer.h

@@ -34,7 +34,7 @@ void aEnvMixerImpl(uint8_t flags, ENVMIX_STATE state, int16_t some_vol);
 void aSetVolumeImpl(uint8_t flags, int16_t v, int16_t t, int16_t r);
 void aPoleFilterImpl(uint8_t flags, int16_t gain, uint32_t t, uint32_t addr);
 void aDisableImpl(uint16_t outp, uint32_t b, uint32_t c);
-void aPlayMP3Impl(const void *mp3file, u32 mp3size, void *out);
+void aPlayMP3Impl(const void *mp3file, u32 mp3size, void *out, int reset);
 
 #define aDisable(pkt, o, b, c) aDisableImpl(o, b, c)
 #define aClearBuffer(pkt, d, c) aClearBufferImpl(d, c)
@@ -50,6 +50,6 @@ void aPlayMP3Impl(const void *mp3file, u32 mp3size, void *out);
 #define aEnvMixer(pkt, f, t, s) aEnvMixerImpl(f, (void *)(s), t)
 #define aSetVolume(pkt, f, v, t, r) aSetVolumeImpl(f, v, t, r)
 #define aPoleFilter(pkt, f, g, t, s) aPoleFilterImpl(f, g, t, s)
-#define aPlayMP3(pkt, a, b, c) aPlayMP3Impl((void *)(a), b, (void *)(c))
+#define aPlayMP3(pkt, a, b, c, r) aPlayMP3Impl((void *)(a), b, (void *)(c), r)
 
 #endif

port/src/mixer.c

@@ -681,12 +681,12 @@ void aSetVolumeImpl(uint8_t flags, int16_t v, int16_t t, int16_t r) {
     }
 }
 
-void aPlayMP3Impl(const void *mp3file, u32 mp3size, void *out) {
+void aPlayMP3Impl(const void *mp3file, u32 mp3size, void *out, int reset) {
     static mp3dec_t mp3d;
     static const u8 *curdata = NULL; // pointer to the mp3 we're currently processing
     static s32 dataptr = 0; // byte index into curdata
 
-    if (mp3file != curdata) {
+    if (mp3file != curdata || reset) {
         // new mp3, reinit decoder
         mp3dec_init(&mp3d);
         curdata = mp3file;

src/include/types.h

@@ -5695,6 +5695,9 @@ struct mp3vars {
 	/*0x5e*/ s16 var8009c3ee;
 	/*0x60*/ u8 var8009c3f0;
 	/*0x61*/ u8 var8009c3f1;
+#ifndef PLATFORM_N64
+	/*0x62*/ u8 reset;
+#endif
 };
 
 struct rdptask {

src/lib/mp3.c

@@ -31,7 +31,7 @@
 
 #include "mixer.h"
 
-#define	acmd07(pkt, a, b, c) aPlayMP3(pkt, a, b, c)
+#define	acmd07(pkt, a, b, c, r) aPlayMP3(pkt, a, b, c, r)
 #define	acmd08(pkt, a) do { } while(0)
 
 #endif
@@ -100,6 +100,9 @@ void mp3PlayFile(s32 romaddr, s32 filesize)
 	g_Mp3Vars.var8009c3e8 = 0;
 	g_Mp3Vars.var8009c3e4 = 0x7fff;
 	g_Mp3Vars.var8009c3f0 = 5;
+#ifndef PLATFORM_N64
+	g_Mp3Vars.reset = 1;
+#endif
 
 	mp3Dma();
 
@@ -251,7 +254,8 @@ s32 func00037fc0(s32 arg0, Acmd **cmd)
 					acmd07((*cmd)++, g_Mp3Vars.var8009c3d8, osVirtualToPhysical(sp58));
 #else
 					// hijack the command to pass the entirety of the mp3 data to the mixer
-					acmd07((*cmd)++, g_Mp3Vars.romaddr, g_Mp3Vars.filesize, osVirtualToPhysical(sp58));
+					acmd07((*cmd)++, g_Mp3Vars.romaddr, g_Mp3Vars.filesize, osVirtualToPhysical(sp58), g_Mp3Vars.reset);
+					g_Mp3Vars.reset = 0;
 #endif
 
 					sp58++;