Improve performance by putting more of the code and variables that are called by the DMA0 interrupt into IRAM (3% boost improvement on my test track).

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@8404 a1c6a512-1295-4272-9138-f99709370657

2 files changed, 11 insertions, 14 deletions

diff --git a/apps/pcmbuf.c b/apps/pcmbuf.c
index 66dd47e..2d75185 100644
--- a/apps/pcmbuf.c
+++ b/apps/pcmbuf.c
@@ -46,8 +46,8 @@
 static long pcmbuf_size = 0;      /* Size of the PCM buffer. */
 static char *audiobuffer;
 static long audiobuffer_pos;      /* Current audio buffer write index. */
-long audiobuffer_free;            /* Amount of bytes left in the buffer. */
-static long audiobuffer_fillpos;  /* Amount audiobuffer_pos will be increased. */
+long audiobuffer_free IDATA_ATTR; /* Amount of bytes left in the buffer. */
+static long audiobuffer_fillpos;  /* Amount audiobuffer_pos will be increased.*/
 static char *guardbuf;
 
 static void (*pcmbuf_event_handler)(void);
@@ -81,11 +81,11 @@ struct pcmbufdesc
     int size;
     /* Call this when the buffer has been played */
     void (*callback)(void);
-} pcmbuffers[NUM_PCM_BUFFERS];
+} pcmbuffers[NUM_PCM_BUFFERS] IDATA_ATTR;
 
 volatile int pcmbuf_read_index;
 volatile int pcmbuf_write_index;
-int pcmbuf_unplayed_bytes;
+int pcmbuf_unplayed_bytes IDATA_ATTR;
 int pcmbuf_mix_used_bytes;
 int pcmbuf_watermark;
 void (*pcmbuf_watermark_event)(int bytes_left);
@@ -121,6 +121,7 @@ int pcmbuf_num_used_buffers(void)
     return (pcmbuf_write_index - pcmbuf_read_index) & NUM_PCM_BUFFERS_MASK;
 }
 
+static void pcmbuf_callback(unsigned char** start, long* size) ICODE_ATTR;
 static void pcmbuf_callback(unsigned char** start, long* size)
 {
     struct pcmbufdesc *desc = &pcmbuffers[pcmbuf_read_index];
@@ -206,14 +207,10 @@ void pcmbuf_add_event(void (*event_handler)(void))
 
 unsigned int pcmbuf_get_latency(void)
 {
-    int latency;
+    int latency = (pcmbuf_unplayed_bytes + pcm_get_bytes_waiting()) 
+        * 1000 / 4 / 44100;
     
-    latency = (pcmbuf_unplayed_bytes + pcm_get_bytes_waiting())
-                * 1000 / 4 / 44100;
-    if (latency < 0)
-        latency = 0;
-    
-    return latency;
+    return latency<0?0:latency;
 }
 
 bool pcmbuf_is_lowdata(void)
diff --git a/firmware/pcm_playback.c b/firmware/pcm_playback.c
index fe71fa3..36c6ab6 100644
--- a/firmware/pcm_playback.c
+++ b/firmware/pcm_playback.c
@@ -59,8 +59,8 @@ static bool pcm_playing;
 static bool pcm_paused;
 static int pcm_freq = 0x6; /* 44.1 is default */
 
-static unsigned char *next_start;
-static long next_size;
+static unsigned char *next_start IDATA_ATTR;
+static long next_size IDATA_ATTR;
 
 /* Set up the DMA transfer that kicks in when the audio FIFO gets empty */
 static void dma_start(const void *addr, long size)
@@ -193,7 +193,7 @@ void pcm_set_frequency(unsigned int frequency)
 }
 
 /* the registered callback function to ask for more mp3 data */
-static void (*callback_for_more)(unsigned char**, long*) = NULL;
+static void (*callback_for_more)(unsigned char**, long*) IDATA_ATTR = NULL;
 
 void pcm_play_data(void (*get_more)(unsigned char** start, long* size))
 {