请将下列表格中的空格填入正确数字(每格之第二个指令执

後的結果)(20%)

AL CF ZF SF OF PF mov AL, 127 add AL, -128 11111111 0 0 1 0 1 mov AL, 127 sub AL, -128 11111111 1 0 1 1 1 mov AL, -1 add AL, 1 00000000 1 1 0 0 1 mov AL, 127 inc AL 10000000 X 0 1 1 0 mov AL, 127 neg AL 10000001 1 0 1 0 1 mov AL, 0 neg AL 00000000 0 1 0 0 1

2. mov BL, 59 statement1 statement2 mov AL, 0 jump end1 skip1:

mov AL, 1 end1:

在上面的程式片斷中，若statement1與statement2為下列之指令，請問執行

後AL的值等於多少？(20%) statement1 statement2 AL cmp BL, 58 jc skip1 0 cmp BL, 59 jc skip1 0 cmp BL, 60 jc skip1 1 cmp BL, 60 jnae skip1 1 cmp BL, 60 jge skip1 0 add BL, 129 jae skip1 1 add BL, 129 jnge skip1 1 add BL, 197 jz skip1 1 mov AL, 10 jo skip1 1 mul BL or BL, BL jp skip1 0

3.請將下列

C語言程式片斷翻譯為組合語言(10%)

for(i = 0; i < 10; i++) index[i] = i;

index DW 10 DUP(?)

mov DI, 0 mov CX, 0 for_loop:

cmp CX, 10 jge end_for

mov index[DI], CX inc CX add DI, 2 jmp for_loop end_for:

4.請用partial evaluation方式將下列之程式用組合語言寫出(10%) if((c != ‘q’) and (c != ‘Q’) and (c >= ‘A’) and (c <= ‘z’)) quit = 0; else

quit = 1;

cmp c, ‘q’ je else_part cmp c, ‘Q’ je else_part cmp c, ‘A’ jb else_part cmp c, ‘z’ ja else_part mov quit, 0 jmp end_if else_part:

mov quit, 1 end_if:

5. Is it possible to set both the overflow and zero flags? If so, give an example that could set both these flags; otherwise, explain why not.(10%) Yes

mov AL, -128 add AL, -128

6. 兩個64位元的數字A, B分別放在暫存器中，A=EBX:EAX, B=EDX:ECX,請寫一個procedure計算A=A-B/2。(20%) addtest PROC

shr EDX, 1 rcr ECX, 1 sub EAX, ECX sbb EBX, EDX ret

addtest ENDP

7. What are forward and backward jumps?(10%)

forward jump:所跳到的目的地是在該jump instruction的下面。

backward jump:所跳到的目的地是在該jump instruction的前面。