//// 进程空间区域写前验证函数。
// 对当前进程的地址addr 到addr+size 这一段进程空间以页为单位执行写操作前的检测操作。
// 若页面是只读的，则执行共享检验和复制页面操作（写时复制）。
void verify_area (void *addr, int size)
{
unsigned long start;
start = (unsigned long) addr;
// 将起始地址start 调整为其所在页的左边界开始位置，同时相应地调整验证区域大小。
// 此时start 是当前进程空间中的线性地址。
size += start & 0xfff;
start &= 0xfffff000;
start += get_base (current->ldt[2]);// 此时start 变成系统整个线性空间中的地址位置。
while (size > 0)
{
size -= 4096;
// 写页面验证。若页面不可写，则复制页面。（mm/memory.c，261 行）
write_verify (start);
start += 4096;
}
}
/*******************************************************************************
Routine Name: main
Form: int main( void )
Parameters: void
Return value: int
but not return...
Description: main
******************************************************************************/
int main( void )
{
unsigned long write_addr;
unsigned char status;
// LED ON, when enter to boot mode
P51D = 1;
P56D = 1;
P56DIR = 0;
P56C1 = 1;
P56C0 = 1;
P56MD0 = 0;
P56MD1 = 0;
P51DIR = 0;
P51C1 = 1;
P51C0 = 1;
P51MD0 = 0;
P51MD1 = 0;
memset(XmodemBuf,0,sizeof(XmodemBuf));
/* initialize variables */
#ifndef DEBUG
write_addr = (unsigned long)USER_AREA_ADDR;
#else
write_addr = (unsigned long)0x2000;
#endif
/* initialize peripheral */
initPeri();
Xmodem_Init( XmodemBuf );
__EI();
// LED ON, when enter to boot mode
/* Display program */
uart_send_sync((unsigned char*)msgIspProg, sizeof(msgIspProg));
Xmodem_SendByte('C');
P51D = 0; // Orange LED ON
/* main loop */
for(;;){
/* clear WDT */
wdt_clear();
status = Xmodem_ReadStatus();
switch(status){
case RECV_END:
P56D = 0; // BLUE LED ON
if(write_verify(&write_addr, XmodemBuf+3) != OK){
error_proc(); /* endless loop in error_proc()*/
}
else{
Xmodem_SendByte(ACK);
}
P56D = 1; // BLUE LED OFF
break;
case EOT_END: // original was remap. change to infinity loop.
end_of_update();
// Remap((unsigned long)USER_AREA_ADDR);
break;
case TIMEOUT_ERR:
case RETRY_ERR:
case SEND_ERR:
#ifdef DEBUG
XmodemBuf[2] = status;
#endif
error_proc(); /* endless loop in error_proc()*/
break;
default:
break;
}
}
}