(→Postfix Code) |
(→Compiling and Running) |
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Consider the following C function: | Consider the following C function: | ||
| − | <c> | + | <source lang="c"> |
int *click(int *x, int dim) { | int *click(int *x, int dim) { | ||
int *res, i; | int *res, i; | ||
| Line 10: | Line 10: | ||
return res; | return res; | ||
} | } | ||
| − | </ | + | </source> |
== Postfix Code == | == Postfix Code == | ||
| Line 16: | Line 16: | ||
The Postfix code for the above function is as follows: | The Postfix code for the above function is as follows: | ||
{{CollapsedCode|Postfix code| | {{CollapsedCode|Postfix code| | ||
| − | <asm> | + | <source lang="asm"> |
TEXT | TEXT | ||
ALIGN | ALIGN | ||
| Line 27: | Line 27: | ||
;; i = dim-2 | ;; i = dim-2 | ||
LOCAL 12 | LOCAL 12 | ||
| − | + | LDINT | |
INT 2 | INT 2 | ||
SUB | SUB | ||
| − | + | DUP32 | |
LOCAL -8 | LOCAL -8 | ||
| − | + | STINT | |
TRASH 4 | TRASH 4 | ||
;; res = x + dim - 1 | ;; res = x + dim - 1 | ||
LOCAL 8 | LOCAL 8 | ||
| − | + | LDINT | |
LOCAL 12 | LOCAL 12 | ||
| − | + | LDINT | |
INT 4 | INT 4 | ||
MUL | MUL | ||
| Line 47: | Line 47: | ||
MUL | MUL | ||
SUB | SUB | ||
| − | + | DUP32 | |
LOCAL -4 | LOCAL -4 | ||
| − | + | STINT | |
TRASH 4 | TRASH 4 | ||
| Line 56: | Line 56: | ||
LABEL for | LABEL for | ||
LOCAL -8 | LOCAL -8 | ||
| − | + | LDINT | |
INT 0 | INT 0 | ||
GE | GE | ||
| Line 65: | Line 65: | ||
;; if test | ;; if test | ||
LOCAL 8 | LOCAL 8 | ||
| − | + | LDINT ; x | |
LOCAL -8 | LOCAL -8 | ||
| − | + | LDINT; i | |
INT 4 | INT 4 | ||
MUL | MUL | ||
ADD ; x+i | ADD ; x+i | ||
| − | + | LDINT ; x[i] = *(x+i) | |
LOCAL -4 | LOCAL -4 | ||
| − | + | LDINT ; res | |
| − | + | LDINT ; *res | |
GT | GT | ||
| Line 82: | Line 82: | ||
;; if block | ;; if block | ||
LOCAL 8 | LOCAL 8 | ||
| − | + | LDINT ; x | |
LOCAL -8 | LOCAL -8 | ||
| − | + | LDINT ; i | |
INT 4 | INT 4 | ||
MUL | MUL | ||
ADD ; x+i = &x[i] | ADD ; x+i = &x[i] | ||
| − | + | DUP32 | |
LOCAL -4 | LOCAL -4 | ||
| − | + | STINT ; res = &x[i] | |
TRASH 4 | TRASH 4 | ||
| Line 100: | Line 100: | ||
LABEL forincr | LABEL forincr | ||
LOCAL -8 | LOCAL -8 | ||
| − | + | LDINT ; i | |
| − | + | DUP32 | |
INT 1 | INT 1 | ||
SUB | SUB | ||
LOCAL -8 | LOCAL -8 | ||
| − | + | STINT | |
TRASH 4 | TRASH 4 | ||
| Line 116: | Line 116: | ||
;; return | ;; return | ||
LOCAL -4 | LOCAL -4 | ||
| − | + | LDINT ; res | |
| − | + | STFVAL32 | |
LEAVE | LEAVE | ||
RET | RET | ||
| − | </ | + | </source> |
}} | }} | ||
== Compiling and Running == | == Compiling and Running == | ||
| − | To compile the Postfix code directly, [[pf2asm]] can be used: | + | To compile the Postfix code directly, [[Compiladores/Projecto de Compiladores/Compiladores Exemplo|pf2asm]] can be used: |
| − | + | pf2asm click.pf | |
| − | + | yasm -felf click.asm | |
[[category:Compiladores]] | [[category:Compiladores]] | ||
[[category:Ensino]] | [[category:Ensino]] | ||
Consider the following C function:
int *click(int *x, int dim) {
int *res, i;
for (i = dim-2, res = x+dim-1; i >= 0; i--)
if (x[i] > *res) res = &x[i];
return res;
}
The Postfix code for the above function is as follows:
| Postfix code |
|---|
TEXT
ALIGN
GLOBL click, FUNC
LABEL click
ENTER 8 ;-- x@+8 dim@+12 res@-4 i@-8
;; for init
;; i = dim-2
LOCAL 12
LDINT
INT 2
SUB
DUP32
LOCAL -8
STINT
TRASH 4
;; res = x + dim - 1
LOCAL 8
LDINT
LOCAL 12
LDINT
INT 4
MUL
ADD
INT 1
INT 4
MUL
SUB
DUP32
LOCAL -4
STINT
TRASH 4
;; for test
ALIGN
LABEL for
LOCAL -8
LDINT
INT 0
GE
JZ forend
;; for block
;; if test
LOCAL 8
LDINT ; x
LOCAL -8
LDINT; i
INT 4
MUL
ADD ; x+i
LDINT ; x[i] = *(x+i)
LOCAL -4
LDINT ; res
LDINT ; *res
GT
JZ ifend
;; if block
LOCAL 8
LDINT ; x
LOCAL -8
LDINT ; i
INT 4
MUL
ADD ; x+i = &x[i]
DUP32
LOCAL -4
STINT ; res = &x[i]
TRASH 4
ALIGN
LABEL ifend
;; for increment
ALIGN
LABEL forincr
LOCAL -8
LDINT ; i
DUP32
INT 1
SUB
LOCAL -8
STINT
TRASH 4
;; for jump to cycle
JMP for
ALIGN
LABEL forend
;; return
LOCAL -4
LDINT ; res
STFVAL32
LEAVE
RET
|
To compile the Postfix code directly, pf2asm can be used:
pf2asm click.pf yasm -felf click.asm