;;; Words doing arithmetics
	
	WORD p_plus, '+',fasm
	;; ( n1 n2 -- n3 )
	;; n3 is the sum of n1 and n2
	pop rax
	add qword [rsp],rax
	next

	WORD p_minus, '-',fasm
	;; ( n1 n2 -- n3 )
	;; n3 is the result of subtracting n2 from n1
	pop rax
	sub qword [rsp], rax
	next

	WORD p_mult, '*',fasm
	;; ( n1 n2 -- n3 )
	;; Multiply n1 by n2 giving the product n3.
	;; [rsp{8}] * [rsp+8{8}]
	;; dd00 = [rsp+4{4}]*[rsp+12{4}] ignored
	;; needs checking !!
	;; 
	;; 0cc0 = [rsp{4}]*[rsp+12{4}]
	mov eax, dword [rsp]
	imul dword [rsp+12]
	mov ebx,eax
	;; 0bb0 = [rsp+4{4}]*[rsp+8{4}]
	mov eax, dword [rsp+4]
	imul dword [rsp+8]
	add ebx, eax
	;; 00aa = [rsp{4}]*[rsp+8{4}]
	mov eax, dword [rsp]
	imul dword [rsp+8]
	add ebx, edx
	shl rbx,32
	mov eax,eax		; ensure zero-extending eax
	add rax, rbx
	push rax
	next

	WORD p_abs, 'ABS',fasm
	;; ( n -- u )
	;; u is the absolute value of n.
	cmp qword [rsp],0
	jge p_abs_end
	neg qword [rsp]
p_abs_end:
	next

	WORD p_negate, 'NEGATE',fasm
	;; ( n1 -- n2 )
	;; Negate n1, giving its arithmetic inverse n2. 
	xor rax,rax
	sub rax,qword [rsp]
	mov qword [rsp],rax
	next