diff options
Diffstat (limited to 'lab7bonus_fig4.s')
| -rw-r--r-- | lab7bonus_fig4.s | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/lab7bonus_fig4.s b/lab7bonus_fig4.s new file mode 100644 index 0000000..35e20e0 --- /dev/null +++ b/lab7bonus_fig4.s @@ -0,0 +1,29 @@ + MOV R6,stack_begin + LDR R6,[R6] // initialize stack pointer + MOV R4, result // R4 contains address of result + MOV R3,#0 + STR R3,[R4] // result = 0; + MOV R0,#1 // R0 contains first parameter + MOV R1,#5 // R1 contains second parameter + MOV R2,#9 // R2 contains third parameter + MOV R3,#20 // R3 contains fourth parameter + BL leaf_example // call leaf_example(1,5,9,20); + STR R0,[R4] // result = leaf_example(1,5,9,20); + HALT +leaf_example: + STR R4,[R6] // save R4 for use afterwards + STR R5,[R6,#-1] // save R5 for use afterwards + ADD R4,R0,R1 // R4 = g + h + ADD R5,R2,R3 // R5 = i + j + MVN R5,R5 // R5 = ~(i + j) + ADD R4,R4,R5 // R4 = (g + h) + ~(i + j) + MOV R5,#1 + ADD R4,R4,R5 // R4 = (g + h) - (i + j) + MOV R0,R4 // R0 = return value (g + h) - (i + j) + LDR R5,[R6,#-1] // restore saved contents of R5 + LDR R4,[R6] // restore saved contents of R4 + BX R7 // return control to caller +stack_begin: + .word 0xFF +result: + .word 0xCCCC |