2009-6-16 Assembler calculate polynom

Calculating polynom with asm and C

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 writed out operation by prioreties [*,+,*,+].
Compiling this with lines
fasm poly.asm poly.o

#include 
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

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

2009-6-16 Assembler calculate polynom

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