Diff: asm_sort.s

Revision:

2:968db132481b

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/asm_sort.s	Sat Jan 04 12:34:04 2020 +0000
@@ -0,0 +1,33 @@
+    AREA asm_func, CODE, READONLY
+    EXPORT asm_sort
+asm_sort
+    PUSH    {R2, R3, R4, R5, LR} ; Some code goes here
+outer_loop
+    LDR R2, =0x0 ;first index
+    LDR R3, =0x1 ;second index
+    SUB R1, R1, #1 ;size of array intervaled minus one
+    CMP R1, #1 ;make sure interval has at least two elements
+    BLT done 
+inner_loop
+    CMP R3, R1 ;compare interval
+    BGT loop_exit ;make sure to restart loop if at the end of first pass
+    LDR R4, [R0, R2, LSL #2] ;numbers[first] into R4
+    LDR R5, [R0, R3, LSL #2] ;number[second] into R5
+    CMP R4, R5 ;compare numbers
+    BGT asm_swap ;if out of order swap
+    ADD R2, R2, #1 ;increment index R2
+    ADD R3, R3, #1 ;increment index R3
+    B inner_loop ; go back to keep swapping
+asm_swap
+    STR     R4, [R0, R3, LSL #2] ;swap numbers in the array
+    STR     R5, [R0, R2, LSL #2]
+    ADD R2, R2, #1 ;increment index
+    ADD R3, R3, #1;increment index
+    B inner_loop ;go back to keep swapping
+loop_exit
+    B outer_loop ;next iteration
+done
+    POP     {R2, R3, R4, R5, LR} ;free regs
+    BX      LR
+    ALIGN
+    END
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