我无法使此代码正常工作,并希望在此处获得一些见解。组装(68k)堆栈操作
该程序应该从输入(> 0和< 300)中读取两个数字并输出它们的总和和乘积。我们应该使用堆栈将值传递给子例程。
我的程序运行并读取输入并显示输出,但它不是正确的输出。我假设我的堆栈操作已关闭,但我无法弄清楚缺少的东西。
这是我的代码到目前为止。
编辑:我有一个功能代码,除了乘法部分。我确信堆栈中的下一个项目是输入数字,但Multiplier子例程不计算正确的产品值。任何人都可以看看这个子程序,并检查什么是错的? ORG $ 1000 START:;程序的第一条指令
* Put program code here
First:
move #14,D0 Display string
lea prompt1,A1
trap #15
move #4,D0 Input num1 to D1
trap #15
move.l D1,-(SP) push num1 to stack
move.l D1,D4 move num1 to keep
move.l #300,D2 Upper limit
cmp D1, D2 Compare user input to upper lim
bhi Second
blo Error1
Second:
move #14,D0 Display string
lea prompt2,A1
trap #15
move #4,D0 Input num2
trap #15
move.l D1,-(SP) push num2
move.l #0,-(SP) make room for sum on the stack
move.l D1,D5 move num2 to keep
move.l #300,D2 Upper limit
cmp D1, D2 Compare user input to upper lim
bhi MoveOn
blo Error2
MoveOn:
*add
bsr Adder
move.l (SP)+,D1 pull sum, D1 = sum
lea (8,SP),SP clean up stack
move #14,D0 Display string
lea result1,A1
trap #15
move #3,D0
trap #15
bsr newLine
move.l D4,-(SP) push num1 to stack
move.l D5,-(SP) push num2 to stack
*multiply
bsr Multiplier
move.l (SP)+,D1 pull product, D1 = prod
lea (8,SP),SP clean up stack
move #14,D0 Display string
lea result2,A1
trap #15
move #3,D0
trap #15
SIMHALT ; halt simulator
Error1:
move #14,D0
lea error,A1
trap #15
move (SP)+,D3 Pull incorrect num1 from stack
bsr newLine
bra First
Error2:
move #14,D0
lea error,A1
trap #15
move (SP)+,D3 Pull incorrect num2 from stack
bsr newLine
bra Second
*----------------------------
offset 4+4
sum ds.l 1
num2 ds.l 1
num1 ds.l 1
org *
Adder
link A0,#0 create stack frame
move.l (num1,A0),D0
add.l (num2,A0),D0
move.l D0,(sum,A0)
move.l (SP)+,D0
unlk A0
rts
*----------------------------
offset 4+4
prod ds.l 1
num4 ds.l 1
num3 ds.l 1
org *
Multiplier
link A0,#0 create stack frame
move.l (num3,A0),D0
mulu (num4,A0),D0
move.l D0,(prod,A0)
move.l (SP)+,D0
unlk A0
rts
newLine
movem.l d0/a1,-(SP) push d0 & a1
move #14,d0 task number into D0
lea crlf,a1 address of string
trap #15 display return, linefeed
movem.l (SP)+,d0/a1 restore d0 & a1
rts return
* Put variables and constants here
prompt1 dc.b 'Sláðu inn fyrri tölu: ',0
prompt2 dc.b 'Sláðu inn seinni tölu: ',0
error dc.b '** Tala er ekki á réttu bili, reyndu aftur **',0
result1 dc.b 'Summa talnanna er: ',0
result2 dc.b 'Margfeldi talnanna er: ',0
crlf dc.b $d,$a,0
END START ; last line of source
你通过调试运行呢? – Devolus
只是一个语义评论:*从堆栈中推送不正确的num2 *。从堆栈中“弹出”,而不是从堆栈中“推出”。:) – lurker
我正在使用easy68k,调试器在哪里? – user2750354