global compute

section .text

;
; calculating functions (sine, cosine, tangent, catangent)
; [ebp+8] is integer angle
; [ebp+12] is pointer to sine buffer
; [ebp+16] is pointer to cosine buffer
; [ebp+20] is pointer to tangent buffer
; [ebp+24] is pointer to catangent buffer
;
compute:	push ebp
		mov ebp, esp
		sub esp, 4
		mov dword [ebp-4], 180
		finit
		fild dword [ebp+8]
		fldpi
		fmulp
		fild dword [ebp-4]
		fdivp
		fld st0				; copy radian angle
		fsin
		mov eax, [ebp+12]
		fstp dword [eax]		; extract sin
		fld st0
		fcos
		mov eax, [ebp+16]
		fstp dword [eax]		; extract cos
		mov eax, [ebp+20]		; check tang
		cmp dword [eax], 0ffffffffh	; undefined value
		je .skip
		fptan
		fxch
		fst dword [eax]			; extract tang
.skip:		mov eax, [ebp+24]
		cmp dword [eax], 0ffffffffh
		je .quit
		fdivp				; ctng
		fstp dword [eax]		; extract ctng
.quit:		mov esp, ebp
		pop ebp
		ret