Exercise 1: Write an ARM assembly language routine to count the number of 1s in a 32-bit word in rO and return the result in r1 code LDR r0, = 0x11AB003F MOV r1,#0x0 MOV r2 , #32 MOVS rO'rO, ROR #1 ADDCS r1,r1,#1 SUBS r2, r2 , #1 BNE OnesCount ;dummy value for r1 :clear ones counter use r2 as the loop counter : Repeat: rotate r0 right set flags ;if carry set increment 1s counter : decrement loop counter ;until all bits tested (11 ones) OnesCount If this was a subroutine Count, the code might be: area test, CODE, readwrite ADR Sp, Stackl LDR r2 ,-0xFFFFFFFF STR r2, [sp] :set up dummy r2 ;dummy data ;call routine ; read result BL MOV r3,rl NOP NOP Count Lab 4 exl ; save r2 and return on the stack STMFD sp!, (r2,lr) MOV r1,#0x0 MOV r2,#4 Count Exercise 1: Write an ARM assembly language routine to count the number of 1s in a 32-bit word in rO and return the result in r1 code LDR r0, = 0x11AB003F MOV r1,#0x0 MOV r2 , #32 MOVS rO'rO, ROR #1 ADDCS r1,r1,#1 SUBS r2, r2 , #1 BNE OnesCount ;dummy value for r1 :clear ones counter use r2 as the loop counter : Repeat: rotate r0 right set flags ;if carry set increment 1s counter : decrement loop counter ;until all bits tested (11 ones) OnesCount If this was a subroutine Count, the code might be: area test, CODE, readwrite ADR Sp, Stackl LDR r2 ,-0xFFFFFFFF STR r2, [sp] :set up dummy r2 ;dummy data ;call routine ; read result BL MOV r3,rl NOP NOP Count Lab 4 exl ; save r2 and return on the stack STMFD sp!, (r2,lr) MOV r1,#0x0 MOV r2,#4 Count