forked from len0rd/rockbox
* Apply a a recent, small optimisation from the archos bitmap lcd driver to the charcell driver, and fix comments. * Make the optimisation more safe, and apply that fix to the bitmap driver as well.
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@16089 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Jens Arnold
parent
feefc90a2a
commit
b30ca8ca5a
2 changed files with 19 additions and 23 deletions
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@ -88,7 +88,7 @@ _lcd_write_command:
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* If so, we must disable the interrupt here. */
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mov.b @r3, r0 /* r0 = PBDRL */
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mov r4, r5 /* (fake) end address = current address */
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mov #0, r5 /* fake end address - stop after first iteration */
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or #(LCD_SD), r0 /* r0 |= LCD_SD */
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and #(~(LCD_CS|LCD_DS|LCD_SC)), r0 /* r0 &= ~(LCD_CS|LCD_DS|LCD_SC) */
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@ -320,7 +320,7 @@ _lcd_grey_data:
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sub r10, r8
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mov.l r8, @(4,r5)
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add #8, r5
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cmp/hi r4, r6
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bt .greyloop
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@ -82,7 +82,7 @@
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_lcd_write_command:
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mov.l .lcdr, r3 /* put lcd data port address in r3 */
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mov r4, r1 /* copy data byte to r1 */
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mov #1, r5 /* set byte count to 1 (!) */
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mov #0, r5 /* fake end address - stop after first iteration */
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/* This code will fail if an interrupt changes the contents of PBDRL.
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* If so, we must disable the interrupt here. */
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@ -110,7 +110,7 @@ _lcd_write_command:
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* r1 - command/data byte (copied)
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* r2 - precalculated port value (CS, DS and SC low, SD high)
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* r3 - lcd port address
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* r5 - 1 (byte count for reuse of the loop in _lcd_write_data)
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* r5 - fake end address
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* r6 - data byte (saved)
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* r7 - saved pr
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*/
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@ -119,7 +119,7 @@ _lcd_write_command_e:
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mov.l .lcdr, r3 /* put lcd data port address in r3 */
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mov r4, r1 /* copy data byte to r1 */
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mov r5, r6
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mov #1, r5 /* set byte count to 1 (!) */
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mov #0, r5 /* fake end address - stop after first iteration */
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/* This code will fail if an interrupt changes the contents of PBDRL.
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* If so, we must disable the interrupt here. */
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@ -134,7 +134,6 @@ _lcd_write_command_e:
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lds r7, pr
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mov r6, r1
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mov #1, r5 /* set byte count to 1 (!) */
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or #(LCD_DS|LCD_SD), r0 /* r0 |= LCD_DS|LCD_SD */
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and #(~(LCD_CS|LCD_SC)), r0 /* r0 &= ~(LCD_CS|LCD_SC) */
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bra .single_transfer /* jump into the transfer loop */
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@ -156,14 +155,15 @@ _lcd_write_command_e:
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* Register usage:
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* r0 - scratch
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* r1 - current data byte
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* r2 - precalculated port value (CS and SC low, DS and SD high),
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* negated (neg)!
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* r2 - precalculated port value (CS and SC low, DS and SD high)
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* r3 - lcd port address
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* r4 - current address
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* r5 - end address
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*/
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_lcd_write_data:
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mov.l .lcdr, r3 /* put lcd data port address in r3 */
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nop /* align here */
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add r4, r5 /* end address */
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/* This code will fail if an interrupt changes the contents of PBDRL.
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* If so, we must disable the interrupt here. If disabling interrupts
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@ -189,7 +189,7 @@ _lcd_write_data:
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mov r2, r0 /* copy precalculated port value */
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bt 1f /* data bit = 1? */
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and #(~LCD_SD), r0 /* no: r0 &= ~LCD_SD */
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1:
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1:
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shll r1 /* next shift here for alignment */
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mov.b r0, @r3 /* set data to port */
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or #(LCD_SC), r0 /* rise SC (independent of SD level) */
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@ -198,7 +198,7 @@ _lcd_write_data:
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mov r2, r0
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bt 1f
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and #(~LCD_SD), r0
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1:
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1:
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mov.b r0, @r3
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or #(LCD_SC), r0
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mov.b r0, @r3
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@ -207,7 +207,7 @@ _lcd_write_data:
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mov r2, r0
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bt 1f
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and #(~LCD_SD), r0
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1:
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1:
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shll r1
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mov.b r0, @r3
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or #(LCD_SC), r0
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@ -216,7 +216,7 @@ _lcd_write_data:
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mov r2, r0
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bt 1f
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and #(~LCD_SD), r0
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1:
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1:
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mov.b r0, @r3
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or #(LCD_SC), r0
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mov.b r0, @r3
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@ -225,7 +225,7 @@ _lcd_write_data:
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mov r2, r0
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bt 1f
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and #(~LCD_SD), r0
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1:
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1:
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shll r1
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mov.b r0, @r3
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or #(LCD_SC), r0
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@ -234,7 +234,7 @@ _lcd_write_data:
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mov r2, r0
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bt 1f
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and #(~LCD_SD), r0
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1:
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1:
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mov.b r0, @r3
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or #(LCD_SC), r0
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mov.b r0, @r3
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@ -243,7 +243,7 @@ _lcd_write_data:
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mov r2, r0
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bt 1f
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and #(~LCD_SD), r0
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1:
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1:
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shll r1
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mov.b r0, @r3
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or #(LCD_SC), r0
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@ -252,14 +252,13 @@ _lcd_write_data:
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mov r2, r0
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bt 1f
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and #(~LCD_SD), r0
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1:
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1:
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mov.b r0, @r3
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or #(LCD_SC), r0
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mov.b r0, @r3
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add #-1, r5 /* decrease byte count */
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tst r5, r5 /* r5 == 0 ? */
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bf .multi_transfer /* no: next iteration */
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cmp/hi r4, r5 /* some blocks left? */
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bt .multi_transfer
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or #(LCD_CS|LCD_DS|LCD_SD|LCD_SC),r0 /* restore port */
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rts
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@ -271,6 +270,3 @@ _lcd_write_data:
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.align 2
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.lcdr:
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.long LCDR
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.end:
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.size _lcd_write_command,.end-_lcd_write_command
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