; list_part.asm  a direct coding of  list.c  (list.c included as comments)
;           standard function entry and exit used, not optimized
; Compile:	nasm -f elf list.asm
; link:		gcc -o test_list_str test_list_str.c list.o
; run:		test_list_str
	
; list.c  this or however you wish, is the functions of list.asm
; #include <stdio.h>       ; extern printf   in list.asm                  
	extern	printf

; static char heap[20000]  ; space to store strings, do not reuse or free
; static char *hp = heap;  ; pointer to next available heap space         
; static int  list[1000];  ; space to store list block (2 index+ pointer) 
; static int  lp=1;        ; index to next available list space
; static char *q;          ; a variable pointer
; static int i;            ; a variable index
	section .bss
heap:	resb	20000
list:	resd	1000
q:	resd	1		; may be just in  esi
i:	resd	1		; may be just in  edi
		
	section	.data
hp:	dd	heap		; [hp] is pointer to next free heap
lp:	dd	1
fmt1:	db	"%s",10,0  ; "%s\n" for printf
	
;        +-----------------+   +-----------------+   +-----------------+
; L[0]-> |  index to next----->|  index to next----->|  0              |
;        |  0              |<-----index to prev  |<-----index to prev  |<-L[1]
;        | ptr to heap str |   | ptr to heap str |   | ptr to heap str |
;        +-----------------+   +-----------------+   +-----------------+
; The pointers to heap strings are character pointes to terminated strings.
; The "index" values couls be pointers rather than indices.

; void clear(int *L)       ; initialize front and back pointers to zero 
; {
	global clear
clear:
        push	ebp		; save ebp
        mov	ebp, esp	; ebp is callers stack
        push	ebx		; save registers
        push	edi
	push	esi

;   L[0]=0; ; later, will be index into "front" of list 
;   L[1]=0; ; later, will be index into "back" of list 
        mov	edi,[ebp+8]	; get address of L into edi
        mov	eax,0		; get a 32-bit zero 
        mov	[edi],eax	; L[0]=0
        mov	[edi+4],eax	; L[1]=0

        pop	esi		; restore registers
	pop	edi		; in reverse order
        pop	ebx
        mov	esp,ebp		; restore callers stack frame
        pop	ebp
        ret			; return
; }

	
; void print(int *L)
; {
	global	print
print:

... project 2, implement the remaining "C" code

; void pop_back(int *L)
; {
	global	pop_back
pop_back:

... implement last function
	
; end list_part.asm file