memory.c

COP8 CPU的一个解释型BASIC源码

////////////////////////////////////////////////////////////////
//
//                S C R I P T H E R M
//             A SCRIPTABLE THERMOMETER
// 
// entry of the National Semiconductor COP8FLASH Design Contest
//        submitted by Alberto Ricci Bitti (C) 2001
//              [e-mail]
//
//--------------------------------------------------------------
//       FOR A BETTER VIEW SET TAB SIZE=4, INDENT SIZE=4
//--------------------------------------------------------------
// FILE   : memory.c
// PURPOSE: Virtual memory manager. Makes accesses to both FLASH
//          (COP8 Virtual Eeprom) and RAM (graphics display spare
//          RAM) virtual. Very convenent if are going to experiment
//          alternative storage media (e.g. Microwire memories). 
//          IMPORTANT: valid for a 10MHz crystal only.
//
////////////////////////////////////////////////////////////////


#include <incop8.h>
#include <ioc8cdr.h>
#include "lcd.h"
#include "memory.h"


void clear_ram(void)
{	unsigned int i;
	for (i=0; i < RAM_SIZE; i++)
	{
		poke_ram( i, 0);
	};
}


void copy_flash_to_ram( void )
{	unsigned int i;
	for (i=0; i < RAM_SIZE; i++)
	{
        __disable_interrupt();
        __PGMTIM = 0x7B; // valid for 10MHz crystal only 
		poke_ram( i, __read_flash_byte( i + FLASH_START ));
        __enable_interrupt();
	};
}


void copy_ram_to_flash( void )
{	unsigned int i;
    unsigned char data;
    unsigned int address;
	for (i=0; i < RAM_SIZE; i++)
	{
	    address = i + FLASH_START;
	    data = peek_ram(i);
	    if ((i & 0x7F) == 0) 	
	    {
            __disable_interrupt();
      	    __PGMTIM = 0x7B; // valid for 10MHz crystal only 
	        __page_flash_erase( address );
            __enable_interrupt();
	    };
        __disable_interrupt();
        __PGMTIM = 0x7B; // valid for 10MHz crystal only 
    	__write_flash_byte( address, data );
        __enable_interrupt();
	};
}


static ram_pointer_t cache_address = RAM_SIZE+1;
static unsigned char cache_data    = 255;

unsigned char peek_ram(ram_pointer_t address)
{
    if (address == cache_address)
        return cache_data;
    else
    {
        cache_address = address;
    	LCD_command(SET_ADDRESS_POINTER, address & 0xFF, address >> 8);
	    LCD_command( DATA_READ_INCREMENT, 0, 0 );
	    return cache_data = LCD_read();
	};
}


void poke_ram(ram_pointer_t address, unsigned char data)
{	
    if( !((address == cache_address) && (data == cache_data)) )
    {
    	cache_data = data;
    	cache_address = address;
    	LCD_command( SET_ADDRESS_POINTER, address & 0xFF, address >> 8);
	    LCD_command( DATA_WRITE_INCREMENT, 0, data );
	};
}


unsigned char peek_flash(flash_pointer_t address)
{   unsigned char retval;
    __disable_interrupt();
    __PGMTIM = 0x7B; // valid for 10MHz crystal only 
	retval = __read_flash_byte( address + FLASH_START );
    __enable_interrupt();
	return retval;
}