Sam Vilmenay / Mbed 2 deprecated AssemblySort

Important changes to repositories hosted on mbed.com

Mbed hosted mercurial repositories are deprecated and are due to be permanently deleted in July 2026.

To keep a copy of this software download the repository Zip archive or clone locally using Mercurial.

It is also possible to export all your personal repositories from the account settings page.

Dependencies:   mbed

asm_sort.s@2:968db132481b, 2020-01-04 (annotated)

Committer:
samvilm
Date:
Sat Jan 04 12:34:04 2020 +0000
Revision:
2:968db132481b
Sorts array of numbers in assembly language. Also sorts same array in C to compare and ensure same sorted array is returned.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
samvilm 2:968db132481b 1 AREA asm_func, CODE, READONLY
samvilm 2:968db132481b 2 EXPORT asm_sort
samvilm 2:968db132481b 3 asm_sort
samvilm 2:968db132481b 4 PUSH {R2, R3, R4, R5, LR} ; Some code goes here
samvilm 2:968db132481b 5 outer_loop
samvilm 2:968db132481b 6 LDR R2, =0x0 ;first index
samvilm 2:968db132481b 7 LDR R3, =0x1 ;second index
samvilm 2:968db132481b 8 SUB R1, R1, #1 ;size of array intervaled minus one
samvilm 2:968db132481b 9 CMP R1, #1 ;make sure interval has at least two elements
samvilm 2:968db132481b 10 BLT done
samvilm 2:968db132481b 11 inner_loop
samvilm 2:968db132481b 12 CMP R3, R1 ;compare interval
samvilm 2:968db132481b 13 BGT loop_exit ;make sure to restart loop if at the end of first pass
samvilm 2:968db132481b 14 LDR R4, [R0, R2, LSL #2] ;numbers[first] into R4
samvilm 2:968db132481b 15 LDR R5, [R0, R3, LSL #2] ;number[second] into R5
samvilm 2:968db132481b 16 CMP R4, R5 ;compare numbers
samvilm 2:968db132481b 17 BGT asm_swap ;if out of order swap
samvilm 2:968db132481b 18 ADD R2, R2, #1 ;increment index R2
samvilm 2:968db132481b 19 ADD R3, R3, #1 ;increment index R3
samvilm 2:968db132481b 20 B inner_loop ; go back to keep swapping
samvilm 2:968db132481b 21 asm_swap
samvilm 2:968db132481b 22 STR R4, [R0, R3, LSL #2] ;swap numbers in the array
samvilm 2:968db132481b 23 STR R5, [R0, R2, LSL #2]
samvilm 2:968db132481b 24 ADD R2, R2, #1 ;increment index
samvilm 2:968db132481b 25 ADD R3, R3, #1;increment index
samvilm 2:968db132481b 26 B inner_loop ;go back to keep swapping
samvilm 2:968db132481b 27 loop_exit
samvilm 2:968db132481b 28 B outer_loop ;next iteration
samvilm 2:968db132481b 29 done
samvilm 2:968db132481b 30 POP {R2, R3, R4, R5, LR} ;free regs
samvilm 2:968db132481b 31 BX LR
samvilm 2:968db132481b 32 ALIGN
samvilm 2:968db132481b 33 END