title:Assembler calculate polynomial
keywords:assembler,c,math,polynomial

# Assembler calculate polynomial
Calculating polynomial with asm and C

```asm
format ELF
section ".text" executable
public poly
align 4
poly:
a equ dword [ebp+8]
b equ dword [ebp+12]
c equ dword [ebp+16]
x equ dword [ebp+20]
    ;a*x*x+b*x+c
    push ebp
    mov ebp , esp
    fld c
    fld x
    fld b
    fld x
    fld a
    fmulp st1 , st0
    faddp st1 , st0
    fmulp st1 , st0
    faddp st1 , st0
    pop ebp
    ret
```

For calculating polynomial used polish notation
Wiki
In other words a*x*x+b*x+c to reduce operations changed to (a*x+b)*x+c
and then written out operation by priorities [*,+,*,+].
Compiling this with lines

```
fasm poly.asm poly.o
```

```c
#include <stdio.h>
extern float poly( float , float , float , float );
int main()
{
    float res = poly( 1.0 , 2.0 , 3.0 , 3.0 );
    printf( "%f\n" , res );
    return 0;
}
```


Compiling this with lines
```
gcc -c main.c -o main.o
```
Combining
```
gcc main.o poly.o -o main
```
Update on 06.12.2009
After running dome C code with FPU calculations and -O2 flag 

```asm
format ELF
section ".text" executable
 
public poly
align 4
poly:
a equ dword [ebp+8]
b equ dword [ebp+12]
c equ dword [ebp+16]
x equ dword [ebp+20]
    ;a*x*x+b*x+c
    push ebp
    mov ebp , esp
 
    fld a
    fmul x
    fadd b
    fmul x
    fadd c
     
    pop ebp
    ret
```

Now only 5 instructions


# Links
http://en.wikipedia.org/wiki/Polish_notation