Diff: led_strip_write_color.s

Revision:

8:1578776ceac5

Parent:

7:9a088f042ee0

Child:

9:6ffb85d69eaf

--- a/led_strip_write_color.s	Fri Mar 01 01:16:48 2013 +0000
+++ b/led_strip_write_color.s	Fri Mar 01 02:05:21 2013 +0000
@@ -22,20 +22,20 @@
     ; Additionally, we use these registers:
     ;   R4:  temporary register
     ;   R5:  temporary register
+    ;   R6: shift register that holds the 24-bit color
     ;   R7:  the number of bits we still need to send
-    ;   R12: shift register that holds the 24-bit color
     ;   R13: Link Register, holds return addresses.
 
-    push {r4, r5, r12, r7, lr}  ; Push those registers so we can restore them later.
+    push {r4, r5, r6, r7, lr}  ; Push those registers so we can restore them later.
     
-    ldr r12, [r0]      ; Read the color.  Now we have:     xxBbGgRr
-    rbit r12, r12      ; Reverse the order of the bits:    rRgGbBxx
-    rev r12, r12       ; Reverse the order of the bytes:   xxbBgGrR
+    ldr r6, [r0]       ; Read the color.  Now we have:     xxBbGgRr
+    rbit r6, r6        ; Reverse the order of the bits:    rRgGbBxx
+    rev r6, r6         ; Reverse the order of the bytes:   xxbBgGrR
     mov r7, #24        ; Initialize the loop counter register.
     
 send_led_strip_bit
     str r3, [r1]       ; Drive the line high.
-    rrxs r12, r12      ; Rotate right through carry.
+    rrxs r6, r6        ; Rotate right through carry.
     
     delay #0
     
@@ -53,7 +53,7 @@
     bne send_led_strip_bit    ; Send another bit if we have not reached zero.
     
 led_strip_asm_end
-    pop {r4, r5, r12, r7, lr}
+    pop {r4, r5, r6, r7, lr}
     bx lr