Exercises

Consider the assembly code which the compiler generates for a C function. Explain what each assembly

instruction does and describe the data is in the register.

$dot{s}^5$ void folint$8\_$t ${?}^{*}a,$ int ${32}_t^{*}b,$ float

$000000$ b$5$f$0$ PUSH $\{r4-r7,lr\}$

$000002$ buB $085$ sp$,$sp$,$#O$\backslash$times $14$

$0000044604$MOVr$4,r0$

$000006460d,$MOV,$s,r1$

$0000084616$ MOV r$6,$r$2$

$dot{s}^6,$ volatile int$8\_$t a$1,$ a$2$;

dots$8,$ volatile float $c1,c2$;

dots$9$

cdots$10,$ a$1=15$;

$00000$a$\_270$f MOVS r$7,$#$0$xf

dots$11,a2=-14$;

$00000$ c $200$ d MOVS r$0,$#$0$xd

$00000$ e $43$ cO MVNS r$0,$r$0$

$0000109004$ STR $r0,[sp,$#$010]$

dots$12,*a=a{1}^{*}a2$;

${0000129804}_{?}$ LDR r$0,[$sp$,$#$0\backslash$times $10]$