; Copyright (C) NEC Electronics Corporation 1990,2005
; NEC ELECTRONICS CONFIDENTIAL AND PROPRIETARY
; All rights reserved by NEC Electronics Corporation.
; This program must be used solely for the purpose for which
; it was furnished by NEC Electronics Corporation. No part of this
; program may be reproduced or disclosed to others, in any
; form, without the prior written permission of NEC Electronics
; Corporation. Use of copyright notice does not evidence
; publication of the program.
;-------------------------------------
; W-1 cstart (no init)
;
; Version 4.00 01 Nov 2006
;-------------------------------------
NAME @cstart 利用NAME 指令，声明此模块的名称为@cstart
$INCLUDE (def.inc)
$INCLUDE (macro.inc)
;-----------------------------------------------------------------------------
; declaration of symbol
;
; attention): change to EQU value 1 -> 0 if necessary
;-----------------------------------------------------------------------------
$_IF(_STATIC) 编译器编译开关
FLOATSW EQU 0 ;floating point variables use
$ELSE
FLOATSW EQU 1 ;floating point variables use
$ENDIF
PUBLIC _@cstart,_@cend 定义两个符号（symbol）
$_IF(FLOATSW)
PUBLIC _errno 如果定义了 FLOATSW=1，则定义符号： _errno
$ENDIF
;-----------------------------------------------------------------------------
; external declaration of symbol for stack area
;
; _@STBEG has value of the end address +1 of compiler's stack area.
; _@STBEG is created by linker with -S option.
; Accordingly, specify the -S option when linking.
;-----------------------------------------------------------------------------
声明外部定义的一些符号
EXTRN _main,_@STBEG,_hdwinit 这些符号为函数
EXTRN _?R_INIT,_?R_INIS,_?DATA,_?DATS 此部分的符号为段的结尾地址
;-----------------------------------------------------------------------------
; allocation area which library uses
; _errno errno number code
;-----------------------------------------------------------------------------
$_IF(FLOATSW)
@@DATA DSEG UNITP
_errno: DS 2
$ENDIF
@@VECT00 CSEG AT 0 将 CSEG段（ROM）地址为 0000H 的地方定义一个段，
名字为@@VECT00，并使用 DW指令将此处的值初始化为_@cstart
DW _@cstart
@@LCODE CSEG 在 CSEG段定义一个名字为@@LCODE 的段，
将下面的代码放置在这一区域
_@cstart:
;-----------------------------------------------------------------------------
; setting the register bank RB0 as work register set
;-----------------------------------------------------------------------------
SEL RB0 选择寄存器组 0
;-----------------------------------------------------------------------------
; setting the stack pointer
;
; _@STBEG is created by linker with -S option.
;-----------------------------------------------------------------------------
初始化堆栈指针，_@STBEG是编译器自动产生的
MOVW SP,#_@STBEG ;SP <- stack begin address
调用_hdwinit函数，
CALL !_hdwinit
;-----------------------------------------------------------------------------
; errno are initialized to 0
;
; The positive error number will be set by several libraries at called them.
;-----------------------------------------------------------------------------
$_IF(FLOATSW)
MOVW AX,#0
MOVW !_errno,AX ;errno <- 0
$ENDIF
;-----------------------------------------------------------------------------
; clear saddr
;-----------------------------------------------------------------------------
MOVW HL,#0FE20H-1
MOV B,#0FEDFH-0FE20H+1
MOV A,#0
LSADR1:
MOV [HL+B], A 在此处循环，以将 saddr区域清零
DBNZ B, $LSADR1 saddr：短寻址区，FE20～FF1F处
;-----------------------------------------------------------------------------
; ROM data copy
;-----------------------------------------------------------------------------
; copy external variables having initial value
此部分程序，将有初值的变量，从ROM复制到 RAM（@@INIT 段）中，
有初值的变量放置在@@ R_INIT 段（位于ROM中），
开始地址为_@R_INIT，结束地址为_?R_INIT，
RAM中，@@INIT 段的开始地址为_@INIT。
MOVW HL,#_@R_INIT
MOVW DE,#_@INIT
LINIT1:
MOVW AX,HL
CMPW AX,#_?R_INIT
BZ $LINIT2
MOV A,[HL]
MOV [DE],A
INCW HL
INCW DE
BR $LINIT1
LINIT2: 此部分程序，将无初值的变量，初始化为 0。
RAM 的@@DATA 段用于存放无初值的变量，
开始地址为_@DATA，结束地址为_？DATA MOVW HL,#_@DATA
; copy external variables which doesn't have initial value
LDATA1:
MOVW AX,HL
CMPW AX,#_?DATA
BZ $LDATA2
MOV A,#0
MOV [HL],A
INCW HL
BR $LDATA1
LDATA2: 此部分程序将有初值的sreg型变量，从ROM复制到RAM （@@INIS段）。
ROM中的@@R_INIS 段用于存放有初值的 sreg型变量。
@@R_INIS 段的开始地址为_@R_INIS，结束地址为_?R_INIS，
_@INIS 为@@INIS 段的开始地址
; copy sreg variables having initial value
MOVW HL,#_@R_INIS
MOVW DE,#_@INIS
LINIS1:
MOVW AX,HL
CMPW AX,#_?R_INIS
BZ $LINIS2
MOV A,[HL]
MOV [DE],A
INCW HL
INCW DE
BR $LINIS1
LINIS2: 此部分程序用于初始化无初值的 sreg 型变量为 0。
RAM中的@@DATS 段用于放置无初值的 sreg 型变量，
_@DATS 为其开始地址，_?DATS为其结束地址。
MOVW HL,#_@DATS
; copy sreg variables which doesn't have initial value
LDATS1:
MOVW AX,HL
CMPW AX,#_?DATS
BZ $LDATS2
MOV A,#0
MOV [HL],A
INCW HL
BR $LDATS1
LDATS2:
;
;-----------------------------------------------------------------------------
; call main function
;-----------------------------------------------------------------------------
CALL !_main ;main(); 跳转到主函数
BR $ 跳转到此行地址，第二个$代表本行指令的地址
;
_@cend:
;
;-----------------------------------------------------------------------------
; define segment and label used by ROMable processing
;-----------------------------------------------------------------------------
@@R_INIT CSEG UNITP
_@R_INIT:
@@R_INIS CSEG UNITP
_@R_INIS:
@@INIT DSEG UNITP
_@INIT: @@DATA DSEG UNITP
_@DATA:
@@INIS DSEG SADDRP
_@INIS:
@@DATS DSEG SADDRP
_@DATS:
@@CALT CSEG CALLT0
@@CALF CSEG FIXED
@@CNST CSEG UNITP
@@BITS BSEG
;
END
