## Problema

Considere o seguinte código C++ (assuma que ponteiros e int ocupam 32 bits e que double ocupa 64 bits).

```double *forall(double *v) {
const static int limit = 1024;
for (int i = 0; i < limit; i++) {
v[i] = 3 * i – sizeof(double);
if (v[i] > 2 * i) v[i] = limit;
}
return v;
}
```

O código Postfix correspondente à função é o seguinte (agradece-se a comunicação de questões relativas a este código).

No código Postfix, BB# significa "bloco básico número".

Postfix code
```TEXT
ALIGN
GLOBAL forall, FUNC
LABEL forall
ENTER 4  ; i@-4 v@+8

; define "limit" (this is not an assignment)
RODATA
ALIGN
LABEL limit ; not really this name
SINT 1024
; done - go back to code segment
TEXT
ALIGN

; initialize for-loop control variable (again, not an assignment)
INT 0
LOCAL -4
STINT ; i = 0

; for-loop test
LABEL fortest
LOCAL -4
LDINT ; i
LDINT ; limit
LT ; i<limit
JZ forend

; BEGIN for-loop body

; BEGIN assignment to v[i]

; compute and promote 3*i
INT 3
LOCAL -4 ; &i
LDINT ; i
MUL
INT 8 ; sizeof(double)
SUB
I2D

DUP64 ; implement assignment value

; compute &v[i] == v+i*sizeof(double)
LOCAL +8 ; &v
LDINT ; v
LOCAL -4 ; &i
LDINT ; i
INT 8 ; sizeof(double)
MUL

STDOUBLE ; do assignment of double value

TRASH 8 ; discard value of assignment

; END assignment to v[i]

; if condition
; compute &v[i] == v+i*sizeof(double)
LOCAL +8 ; &v
LDINT ; v
LOCAL -4 ; &i
LDINT ; i
INT 8 ; sizeof(double)
MUL
LDDOUBLE ; v[i]

; compute and promote 2*i
INT 2
LOCAL -4 ; &i
LDINT ; i
MUL
I2D

; compare
DCMP
INT 0
GT

JZ ifend

; BEGIN if block
; do assignment (double)

LDINT
I2D

DDUP ; implement assignment value

; compute &v[i] == v+i*sizeof(double)
LOCAL +8 ; &v
LDINT ; v
LOCAL -4 ; &i
LDINT ; i
INT 8 ; sizeof(double)
MUL

STDOUBLE ; do  assignment of double value

TRASH 8 ; discard value of assignment

; END if block
LABEL ifend

; FOR increment
LABEL forincr

; increment expression
LOCAL -4 ; &i
LDINT ; i
DUP32
INT 1
LOCAL -4 ; &i
STINT
TRASH 4

; END for-loop body
JMP fortest
LABEL forend

; return *v
LOCAL +8 ; &v
LDINT ; v
STFVAL32
LEAVE
RET
```

## Compiling and Running

Para compilar o código Postfix directamente, pode ser utilizada a ferramenta pf2asm (assumindo uma arquitectura de 32 bits):

```pf2asm forall.pf
yasm -felf forall.asm
```