Question

Translate the following C program into an assembly program. The C program finds the minimal value of three signed integers. Assume a, b, and c is stored in register r0, r1, and r3, respectively. The result min is saved in register r4.

If (a< b && a min =a;
} else if (b min=b;
} else {
Min=c:
}

Answer 1

GLOBAL minRoutine

AREA MYCODE, CODE, READONLY

ENTRY

minRoutine

MOV r0, #0xA

MOV r1, #0x3

MOV r3, #0x8

CMP r0,r1

BLT less1Routine

CMP r1,r0

BLT less2Routine

MOV r4,r3

less1Routine

CMP r0,r3

BLT cond1

less2Routine

CMP r1,r3

BLT cond2

cond1

MOV r4,r0

cond2

MOV r4,r1

END

Step-by-step explanation:

• Inside the minRoutine, move the essential values to the r0, r1 and r3 registers.
• Check if a is greater than b by comparing value in r0 with r1.
• Jump to less1Routine, if value of r0 is less than value of r1. Otherwise go to next instruction .
• Check if b is greater than a by comparing value in r1 with r0.
• Jump to less2Routine, if value of r1 is less than value of r0. Otherwise go to next instruction .
• Finally move result of r1 into r4 register.