1bit and 2bit LCD drivers: Low-level bit handling optimisations.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@10225 a1c6a512-1295-4272-9138-f99709370657

apps/plugins/lib/playergfx.c

@@ -152,7 +152,10 @@ static void fgblock(unsigned char *address, unsigned mask, unsigned bits)
 
 static void solidblock(unsigned char *address, unsigned mask, unsigned bits)
 {
-    *address = (*address & ~mask) | (bits & mask);
+    unsigned data = *(char *)address;
+    
+    bits    ^= data;
+    *address = data ^ (bits & mask);
 }
 
 static void flipinvblock(unsigned char *address, unsigned mask, unsigned bits)
@@ -172,7 +175,10 @@ static void fginvblock(unsigned char *address, unsigned mask, unsigned bits)
 
 static void solidinvblock(unsigned char *address, unsigned mask, unsigned bits)
 {
-    *address = (*address & ~mask) | (~bits & mask);
+    unsigned data = *(char *)address;
+    
+    bits     = ~bits ^ data;
+    *address = data ^ (bits & mask);
 }
 
 lcd_blockfunc_type* pgfx_blockfuncs[8] = {

firmware/drivers/lcd-2bit-horz.c

@@ -197,24 +197,29 @@ static void bgblock(unsigned char *address, unsigned mask, unsigned bits)
                     ICODE_ATTR;
 static void bgblock(unsigned char *address, unsigned mask, unsigned bits)
 {
-    mask &= ~bits;
-    *address = (*address & ~mask) | (bg_pattern & mask);
+    unsigned data = *address;
+
+    *address = data ^ ((data ^ bg_pattern) & mask & ~bits);
 }
 
 static void fgblock(unsigned char *address, unsigned mask, unsigned bits)
                     ICODE_ATTR;
 static void fgblock(unsigned char *address, unsigned mask, unsigned bits)
 {
-    mask &= bits;
-    *address = (*address & ~mask) | (fg_pattern & mask);
+    unsigned data = *address;
+
+    *address = data ^ ((data ^ fg_pattern) & mask & bits);
 }
 
 static void solidblock(unsigned char *address, unsigned mask, unsigned bits)
                        ICODE_ATTR;
 static void solidblock(unsigned char *address, unsigned mask, unsigned bits)
 {
-    *address = (*address & ~mask) | (bits & mask & fg_pattern)
-                                  | (~bits & mask & bg_pattern);
+    unsigned data = *address;
+    unsigned bgp  = bg_pattern;
+
+    bits     = bgp  ^ ((bgp ^ fg_pattern) & bits);
+    *address = data ^ ((data ^ bits) & mask);
 }
 
 static void flipinvblock(unsigned char *address, unsigned mask, unsigned bits)
@@ -228,24 +233,29 @@ static void bginvblock(unsigned char *address, unsigned mask, unsigned bits)
                        ICODE_ATTR;
 static void bginvblock(unsigned char *address, unsigned mask, unsigned bits)
 {
-    mask &= bits;
-    *address = (*address & ~mask) | (bg_pattern & mask);
+    unsigned data = *address;
+
+    *address = data ^ ((data ^ bg_pattern) & mask & bits);
 }
 
 static void fginvblock(unsigned char *address, unsigned mask, unsigned bits)
                        ICODE_ATTR;
 static void fginvblock(unsigned char *address, unsigned mask, unsigned bits)
 {
-    mask &= ~bits;
-    *address = (*address & ~mask) | (fg_pattern & mask);
+    unsigned data = *address;
+
+    *address = data ^ ((data ^ fg_pattern) & mask & ~bits);
 }
 
 static void solidinvblock(unsigned char *address, unsigned mask, unsigned bits)
                           ICODE_ATTR;
 static void solidinvblock(unsigned char *address, unsigned mask, unsigned bits)
 {
-    *address = (*address & ~mask) | (~bits & mask & fg_pattern)
-                                  | (bits & mask & bg_pattern);
+    unsigned data = *address;
+    unsigned fgp  = fg_pattern;
+
+    bits     = fgp  ^ ((fgp ^ bg_pattern) & bits);
+    *address = data ^ ((data ^ bits) & mask);
 }
 
 lcd_blockfunc_type* const lcd_blockfuncs[8] = {
@@ -255,7 +265,10 @@ lcd_blockfunc_type* const lcd_blockfuncs[8] = {
 
 static inline void setblock(unsigned char *address, unsigned mask, unsigned bits)
 {
-    *address = (*address & ~mask) | (bits & mask);
+    unsigned data = *address;
+    
+    bits    ^= data;
+    *address = data ^ (bits & mask);
 }
 
 /*** drawing functions ***/

firmware/drivers/lcd-h100-remote.c

@@ -716,7 +716,10 @@ static void solidblock(unsigned char *address, unsigned mask, unsigned bits)
                        ICODE_ATTR;
 static void solidblock(unsigned char *address, unsigned mask, unsigned bits)
 {
-    *address = (*address & ~mask) | (bits & mask);
+    unsigned data = *address;
+    
+    bits    ^= data;
+    *address = data ^ (bits & mask);
 }
 
 static void flipinvblock(unsigned char *address, unsigned mask, unsigned bits)
@@ -744,7 +747,10 @@ static void solidinvblock(unsigned char *address, unsigned mask, unsigned bits)
                           ICODE_ATTR;
 static void solidinvblock(unsigned char *address, unsigned mask, unsigned bits)
 {
-    *address = (*address & ~mask) | (~bits & mask);
+    unsigned data = *address;
+    
+    bits     = ~bits ^ data;
+    *address = data ^ (bits & mask);
 }
 
 lcd_blockfunc_type* const lcd_remote_blockfuncs[8] = {

firmware/drivers/lcd-h100.c

@@ -397,24 +397,29 @@ static void bgblock(unsigned char *address, unsigned mask, unsigned bits)
                     ICODE_ATTR;
 static void bgblock(unsigned char *address, unsigned mask, unsigned bits)
 {
-    mask &= ~bits;
-    *address = (*address & ~mask) | (bg_pattern & mask);
+    unsigned data = *address;
+
+    *address = data ^ ((data ^ bg_pattern) & mask & ~bits);
 }
 
 static void fgblock(unsigned char *address, unsigned mask, unsigned bits)
                     ICODE_ATTR;
 static void fgblock(unsigned char *address, unsigned mask, unsigned bits)
 {
-    mask &= bits;
-    *address = (*address & ~mask) | (fg_pattern & mask);
+    unsigned data = *address;
+
+    *address = data ^ ((data ^ fg_pattern) & mask & bits);
 }
 
 static void solidblock(unsigned char *address, unsigned mask, unsigned bits)
                        ICODE_ATTR;
 static void solidblock(unsigned char *address, unsigned mask, unsigned bits)
 {
-    *address = (*address & ~mask) | (bits & mask & fg_pattern)
-                                  | (~bits & mask & bg_pattern);
+    unsigned data = *address;
+    unsigned bgp  = bg_pattern;
+    
+    bits     = bgp  ^ ((bgp ^ fg_pattern) & bits);
+    *address = data ^ ((data ^ bits) & mask);
 }
 
 static void flipinvblock(unsigned char *address, unsigned mask, unsigned bits)
@@ -428,24 +433,29 @@ static void bginvblock(unsigned char *address, unsigned mask, unsigned bits)
                        ICODE_ATTR;
 static void bginvblock(unsigned char *address, unsigned mask, unsigned bits)
 {
-    mask &= bits;
-    *address = (*address & ~mask) | (bg_pattern & mask);
+    unsigned data = *address;
+
+    *address = data ^ ((data ^ bg_pattern) & mask & bits);
 }
 
 static void fginvblock(unsigned char *address, unsigned mask, unsigned bits)
                        ICODE_ATTR;
 static void fginvblock(unsigned char *address, unsigned mask, unsigned bits)
 {
-    mask &= ~bits;
-    *address = (*address & ~mask) | (fg_pattern & mask);
+    unsigned data = *address;
+
+    *address = data ^ ((data ^ fg_pattern) & mask & ~bits);
 }
 
 static void solidinvblock(unsigned char *address, unsigned mask, unsigned bits)
                           ICODE_ATTR;
 static void solidinvblock(unsigned char *address, unsigned mask, unsigned bits)
 {
-    *address = (*address & ~mask) | (~bits & mask & fg_pattern)
-                                  | (bits & mask & bg_pattern);
+    unsigned data = *address;
+    unsigned fgp  = fg_pattern;
+    
+    bits     = fgp  ^ ((fgp ^ bg_pattern) & bits);
+    *address = data ^ ((data ^ bits) & mask);
 }
 
 lcd_blockfunc_type* const lcd_blockfuncs[8] = {
@@ -455,7 +465,10 @@ lcd_blockfunc_type* const lcd_blockfuncs[8] = {
 
 static inline void setblock(unsigned char *address, unsigned mask, unsigned bits)
 {
-    *address = (*address & ~mask) | (bits & mask);
+    unsigned data = *address;
+
+    bits    ^= data;
+    *address = data ^ (bits & mask);
 }
 
 /*** drawing functions ***/

firmware/drivers/lcd-recorder.c

@@ -441,7 +441,10 @@ static void solidblock(unsigned char *address, unsigned mask, unsigned bits)
                        ICODE_ATTR;
 static void solidblock(unsigned char *address, unsigned mask, unsigned bits)
 {
-    *address = (*address & ~mask) | (bits & mask);
+    unsigned data = *(char*)address;
+
+    bits    ^= data;
+    *address = data ^ (bits & mask);
 }
 
 static void flipinvblock(unsigned char *address, unsigned mask, unsigned bits)
@@ -469,7 +472,10 @@ static void solidinvblock(unsigned char *address, unsigned mask, unsigned bits)
                           ICODE_ATTR;
 static void solidinvblock(unsigned char *address, unsigned mask, unsigned bits)
 {
-    *address = (*address & ~mask) | (~bits & mask);
+    unsigned data = *(char *)address;
+    
+    bits     = ~bits ^ data;
+    *address = data ^ (bits & mask);
 }
 
 lcd_blockfunc_type* const lcd_blockfuncs[8] = {