Summer2015 Day3 Quiz1.1

quiz1.1.c

@prologue...
@move x to r0
@r2=n=1
cmp r0, #0
beq .L6
LSR r1, r0, LSR #16
 cmp r1 #0
 beq .L1;
LSR r1, r0, LSR #24
 cmp r1 #0
 beq .L2;
LSR r1, r0, LSR #28
 cmp r1, #0
 beq .L3; 
LSR r1, r0, LSR #30
 cmp r1 #0
 beq .L4;
 .L1:
 add r2, r2, #16
 LSL r0, r0, #16
 bl .L5
 .L2:
 add r2, r2, #8
 LSL r0, r0, #8
 bl .L5
 .L3:
 add r2, r2, #4
 LSL r0, r0, #4
 bl .L5
 .L4:
 add r2, r2, #2
 LSL r0, r0, #2
 bl .L5
 .L5:
LSR r1, r0, #31 
SUB r2, r2, r1
mov r0, r2
.L6
mov r0, 32
 @epilogue...
 再來算branch數量 約8個