Inspired by patch #1377739 by Brandon Low: Inline oggpack_adv and the most used part of oggpack_look. Reduces CPU boost on a test track (208 kbps) by 2-3 percentage points.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@8274 a1c6a512-1295-4272-9138-f99709370657

apps/codecs/Tremor/bitwise.c

@@ -22,45 +22,6 @@
 #include <string.h>
 #include "ogg.h"
 
-static const unsigned long mask[] ICONST_ATTR =
-{0x00000000,0x00000001,0x00000003,0x00000007,0x0000000f,
- 0x0000001f,0x0000003f,0x0000007f,0x000000ff,0x000001ff,
- 0x000003ff,0x000007ff,0x00000fff,0x00001fff,0x00003fff,
- 0x00007fff,0x0000ffff,0x0001ffff,0x0003ffff,0x0007ffff,
- 0x000fffff,0x001fffff,0x003fffff,0x007fffff,0x00ffffff,
- 0x01ffffff,0x03ffffff,0x07ffffff,0x0fffffff,0x1fffffff,
- 0x3fffffff,0x7fffffff,0xffffffff };
-
-/* mark read process as having run off the end */
-static void _adv_halt(oggpack_buffer *b){
-  b->headptr=b->head->buffer->data+b->head->begin+b->head->length;
-  b->headend=-1;
-  b->headbit=0;
-}
-
-/* spans forward, skipping as many bytes as headend is negative; if
-   headend is zero, simply finds next byte.  If we're up to the end
-   of the buffer, leaves headend at zero.  If we've read past the end,
-   halt the decode process. */
-static void _span(oggpack_buffer *b){
-  while(b->headend<1){
-    if(b->head->next){
-      b->count+=b->head->length;
-      b->head=b->head->next;
-      b->headptr=b->head->buffer->data+b->head->begin-b->headend; 
-      b->headend+=b->head->length;      
-    }else{
-      /* we've either met the end of decode, or gone past it. halt
-         only if we're past */
-      if(b->headend<0 || b->headbit)
-        /* read has fallen off the end */
-        _adv_halt(b);
-
-      break;
-    }
-  }
-}
-
 void oggpack_readinit(oggpack_buffer *b,ogg_reference *r){
   memset(b,0,sizeof(*b));
 
@@ -79,9 +40,9 @@ void oggpack_readinit(oggpack_buffer *b,ogg_reference *r){
                       }
 
 /* Read in bits without advancing the bitptr; bits <= 32 */
-long oggpack_look(oggpack_buffer *b,int bits) ICODE_ATTR;
+long oggpack_look_full(oggpack_buffer *b,int bits) ICODE_ATTR;
-long oggpack_look(oggpack_buffer *b,int bits){
+long oggpack_look_full(oggpack_buffer *b,int bits){
-  unsigned long m=mask[bits];
+  unsigned long m=(1<<bits)-1;
   unsigned long ret=0;
 
   bits+=b->headbit;
@@ -139,19 +100,6 @@ long oggpack_look(oggpack_buffer *b,int bits){
   return ret;
 }
 
-/* limited to 32 at a time */
-#if CONFIG_CPU!=PP5020
-/* TODO: This function (and this function only) causes a "relocation
-   truncated to fit: R_ARM_PC24" error when in IRAM on ARM targets */
-void oggpack_adv(oggpack_buffer *b,int bits) ICODE_ATTR;
-#endif
-void oggpack_adv(oggpack_buffer *b,int bits){
-  bits+=b->headbit;
-  b->headbit=bits&7;
-  b->headptr+=bits/8;
-  if((b->headend-=bits/8)<1)_span(b);
-}
-
 /* spans forward and finds next byte.  Never halts */
 static void _span_one(oggpack_buffer *b){
   while(b->headend<1){
@@ -180,7 +128,7 @@ int oggpack_eop(oggpack_buffer *b){
 
 /* bits <= 32 */
 long oggpack_read(oggpack_buffer *b,int bits){
-  unsigned long m=mask[bits];
+  unsigned long m=(1<<bits)-1;
   ogg_uint32_t ret=0;
 
   bits+=b->headbit;
@@ -235,7 +183,7 @@ long oggpack_read(oggpack_buffer *b,int bits){
       }
     }
   }else{
-  
+
     ret=b->headptr[0]>>b->headbit;
     if(bits>8){
       ret|=b->headptr[1]<<(8-b->headbit);  

apps/codecs/Tremor/ogg.h

@@ -141,13 +141,76 @@ typedef struct {
 /* Ogg BITSTREAM PRIMITIVES: bitstream ************************/
 
 extern void  oggpack_readinit(oggpack_buffer *b,ogg_reference *r);
-extern long  oggpack_look(oggpack_buffer *b,int bits);
+extern long  oggpack_look_full(oggpack_buffer *b,int bits);
-extern void  oggpack_adv(oggpack_buffer *b,int bits);
 extern long  oggpack_read(oggpack_buffer *b,int bits);
 extern long  oggpack_bytes(oggpack_buffer *b);
 extern long  oggpack_bits(oggpack_buffer *b);
 extern int   oggpack_eop(oggpack_buffer *b);
 
+/* Inline a few, often called functions */
+
+/* mark read process as having run off the end */
+static inline void _adv_halt(oggpack_buffer *b){
+  b->headptr=b->head->buffer->data+b->head->begin+b->head->length;
+  b->headend=-1;
+  b->headbit=0;
+}
+
+/* spans forward, skipping as many bytes as headend is negative; if
+   headend is zero, simply finds next byte.  If we're up to the end
+   of the buffer, leaves headend at zero.  If we've read past the end,
+   halt the decode process. */
+static inline void _span(oggpack_buffer *b){
+  while(b->headend<1){
+    if(b->head->next){
+      b->count+=b->head->length;
+      b->head=b->head->next;
+      b->headptr=b->head->buffer->data+b->head->begin-b->headend; 
+      b->headend+=b->head->length;      
+    }else{
+      /* we've either met the end of decode, or gone past it. halt
+         only if we're past */
+      if(b->headend<0 || b->headbit)
+        /* read has fallen off the end */
+        _adv_halt(b);
+
+      break;
+    }
+  }
+}
+
+/* limited to 32 at a time */
+static inline void oggpack_adv(oggpack_buffer *b,int bits){
+  bits+=b->headbit;
+  b->headbit=bits&7;
+  b->headptr+=bits/8;
+  if((b->headend-=bits/8)<1)_span(b);
+}
+
+static inline long oggpack_look(oggpack_buffer *b, int bits){
+  if(bits+b->headbit < b->headend<<3){
+    unsigned long m=(1<<bits)-1;
+    unsigned long ret=0;
+
+    bits+=b->headbit;
+    ret=b->headptr[0]>>b->headbit;
+    if(bits>8){
+      ret|=b->headptr[1]<<(8-b->headbit);  
+      if(bits>16){
+        ret|=b->headptr[2]<<(16-b->headbit);  
+        if(bits>24){
+          ret|=b->headptr[3]<<(24-b->headbit);  
+          if(bits>32 && b->headbit)
+            ret|=b->headptr[4]<<(32-b->headbit);
+        }
+      }
+    }
+    return ret&m;
+  }else{
+    return oggpack_look_full(b, bits);
+  }
+}
+
 /* Ogg BITSTREAM PRIMITIVES: decoding **************************/
 
 extern ogg_sync_state *ogg_sync_create(void);