* ARM asm DSP and codec/plugin functions: Use r12 scratch register properly

* Fix saving another unused reg in dsp code
* Use less regs in the generic ARM mpegplayer adding idct pure DC case
* Fix ARMv6 mpegplayer adding idct using an unsaved register in pure DC case


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@21803 a1c6a512-1295-4272-9138-f99709370657

2 files changed, 51 insertions, 53 deletions

diff --git a/apps/plugins/mpegplayer/idct_arm.S b/apps/plugins/mpegplayer/idct_arm.S
index 7de2d7f..3cb1554 100644
--- a/apps/plugins/mpegplayer/idct_arm.S
+++ b/apps/plugins/mpegplayer/idct_arm.S
@@ -268,7 +268,7 @@
     bx     lr
 
 mpeg2_idct_copy:
-    stmfd  sp!, { r1-r2, r4-r12, lr }
+    stmfd  sp!, { r1-r2, r4-r11, lr }
     bl     .idct
     ldmfd  sp!, { r1-r2 }
     mov    r11, #0
@@ -313,7 +313,7 @@ mpeg2_idct_copy:
     add    r1, r1, r2
     cmp    r0, r12
     blo    1b
-    ldmfd  sp!, { r4-r12, pc }
+    ldmfd  sp!, { r4-r11, pc }
 
 mpeg2_idct_add:
     cmp    r0, #129
@@ -324,7 +324,7 @@ mpeg2_idct_add:
     cmp    r1, #0x40
     bne    3f
 1:
-    stmfd  sp!, { r2-r12, lr }
+    stmfd  sp!, { r2-r11, lr }
     bl     .idct
     ldmfd  sp!, { r1-r2 }
     mov    r11, #0
@@ -385,24 +385,20 @@ mpeg2_idct_add:
     add    r1, r1, r2
     cmp    r0, r12
     blo    2b
-    ldmfd  sp!, { r4-r12, pc }
+    ldmfd  sp!, { r4-r11, pc }
 3:
-    stmfd  sp!, { r4-r11 }
+    stmfd  sp!, { r4-r6, lr }
     ldrsh  r1, [r0, #0]           /* r1 = block[0] */
-    mov    r11, #0
-    strh   r11, [r0, #0]          /* block[0] = 0 */
-    strh   r11, [r0, #126]        /* block[63] = 0 */
+    mov    r4, #0
+    strh   r4, [r0, #0]           /* block[0] = 0 */
+    strh   r4, [r0, #126]         /* block[63] = 0 */
     add    r1, r1, #64            /* r1 = DC << 7 */
     add    r0, r2, r3, asl #3
 4:
     ldrb   r4, [r2, #0]
     ldrb   r5, [r2, #1]
     ldrb   r6, [r2, #2]
-    ldrb   r7, [r2, #3]
-    ldrb   r8, [r2, #4]
-    ldrb   r9, [r2, #5]
-    ldrb   r10, [r2, #6]
-    ldrb   r11, [r2, #7]
+    ldrb   lr, [r2, #3]
     add    r4, r4, r1, asr #7
     cmp    r4, #255
     mvnhi  r4, r4, asr #31
@@ -415,28 +411,31 @@ mpeg2_idct_add:
     cmp    r6, #255
     mvnhi  r6, r6, asr #31
     strb   r6, [r2, #2]
-    add    r7, r7, r1, asr #7
-    cmp    r7, #255
-    mvnhi  r7, r7, asr #31
-    strb   r7, [r2, #3]
-    add    r8, r8, r1, asr #7
-    cmp    r8, #255
-    mvnhi  r8, r8, asr #31
-    strb   r8, [r2, #4]
-    add    r9, r9, r1, asr #7
-    cmp    r9, #255
-    mvnhi  r9, r9, asr #31
-    strb   r9, [r2, #5]
-    add    r10, r10, r1, asr #7
-    cmp    r10, #255
-    mvnhi  r10, r10, asr #31
-    strb   r10, [r2, #6]
-    add    r11, r11, r1, asr #7
-    cmp    r11, #255
-    mvnhi  r11, r11, asr #31
-    strb   r11, [r2, #7]
+    add    lr, lr, r1, asr #7
+    cmp    lr, #255
+    mvnhi  lr, lr, asr #31
+    strb   lr, [r2, #3]
+    ldrb   r4, [r2, #4]
+    ldrb   r5, [r2, #5]
+    ldrb   r6, [r2, #6]
+    ldrb   lr, [r2, #7]
+    add    r4, r4, r1, asr #7
+    cmp    r4, #255
+    mvnhi  r4, r4, asr #31
+    strb   r4, [r2, #4]
+    add    r5, r5, r1, asr #7
+    cmp    r5, #255
+    mvnhi  r5, r5, asr #31
+    strb   r5, [r2, #5]
+    add    r6, r6, r1, asr #7
+    cmp    r6, #255
+    mvnhi  r6, r6, asr #31
+    strb   r6, [r2, #6]
+    add    lr, lr, r1, asr #7
+    cmp    lr, #255
+    mvnhi  lr, lr, asr #31
+    strb   lr, [r2, #7]
     add    r2, r2, r3
     cmp    r2, r0
     blo    4b
-    ldmfd  sp!, { r4-r11 }
-    bx     lr
+    ldmfd  sp!, { r4-r6, pc }
diff --git a/apps/plugins/mpegplayer/idct_armv6.S b/apps/plugins/mpegplayer/idct_armv6.S
index 73feed4..ca97d12 100644
--- a/apps/plugins/mpegplayer/idct_armv6.S
+++ b/apps/plugins/mpegplayer/idct_armv6.S
@@ -196,7 +196,7 @@ L_W0246:
 
 
 mpeg2_idct_copy:
-    stmfd  sp!, {r1-r2, r4-r12, lr}
+    stmfd  sp!, {r1-r2, r4-r11, lr}
     bl     .idct
     ldmfd  sp!, {r1-r2}
 
@@ -230,7 +230,7 @@ mpeg2_idct_copy:
     cmp    r0, r12
     blo    1b
 
-    ldmfd  sp!, {r4-r12, pc}
+    ldmfd  sp!, {r4-r11, pc}
 
 mpeg2_idct_add:
     cmp    r0, #129
@@ -241,7 +241,7 @@ mpeg2_idct_add:
     cmp    r1, #0x40
     bne    3f
 1:
-    stmfd  sp!, {r2-r12, lr}
+    stmfd  sp!, {r2-r11, lr}
     bl     .idct
     ldmfd  sp!, {r1-r2}
     mov    r11, #0
@@ -287,21 +287,21 @@ mpeg2_idct_add:
     add    r1, r1, r2
     cmp    r0, r12
     blo    2b
-    ldmfd  sp!, {r4-r12, pc}
+    ldmfd  sp!, {r4-r11, pc}
 
 3:
-    stmfd  sp!, {r4-r7}
+    stmfd  sp!, {r4-r6, lr}
     ldrsh  r1, [r0, #0]           /* r1 = block[0] */
-    mov    r11, #0
-    strh   r11, [r0, #0]          /* block[0] = 0 */
-    strh   r11, [r0, #126]        /* block[63] = 0 */
+    mov    r4, #0
+    strh   r4, [r0, #0]           /* block[0] = 0 */
+    strh   r4, [r0, #126]         /* block[63] = 0 */
     add    r1, r1, #64            /* r1 = DC << 7 */
     add    r0, r2, r3, asl #3
 4:
     ldrb   r4, [r2, #0]
     ldrb   r5, [r2, #1]
     ldrb   r6, [r2, #2]
-    ldrb   r7, [r2, #3]
+    ldrb   lr, [r2, #3]
     add    r4, r4, r1, asr #7
     usat   r4, #8, r4
     strb   r4, [r2, #0]
@@ -311,13 +311,13 @@ mpeg2_idct_add:
     add    r6, r6, r1, asr #7
     usat   r6, #8, r6
     strb   r6, [r2, #2]
-    add    r7, r7, r1, asr #7
-    usat   r7, #8, r7
-    strb   r7, [r2, #3]
+    add    lr, lr, r1, asr #7
+    usat   lr, #8, lr
+    strb   lr, [r2, #3]
     ldrb   r4, [r2, #4]
     ldrb   r5, [r2, #5]
     ldrb   r6, [r2, #6]
-    ldrb   r7, [r2, #7]
+    ldrb   lr, [r2, #7]
     add    r4, r4, r1, asr #7
     usat   r4, #8, r4
     strb   r4, [r2, #4]
@@ -327,11 +327,10 @@ mpeg2_idct_add:
     add    r6, r6, r1, asr #7
     usat   r6, #8, r6
     strb   r6, [r2, #6]
-    add    r7, r7, r1, asr #7
-    usat   r7, #8, r7
-    strb   r7, [r2, #7]
+    add    lr, lr, r1, asr #7
+    usat   lr, #8, lr
+    strb   lr, [r2, #7]
     add    r2, r2, r3
     cmp    r2, r0
     blo    4b
-    ldmfd  sp!, {r4-r7}
-    bx     lr
+    ldmfd  sp!, {r4-r6, pc}