module.h

00001 // -------------------------------------------------------------
00002 // BBC Basic hardware emulation part
00003 // -------------------------------------------------------------
00004 
00005 #include "bbc_0100.h"
00006 
00007 #include "mbed.h"
00008 #define byte unsigned char
00009 #define word unsigned short
00010 
00011 // some defaults
00012 #define ESCFLG  0xff80          // escape flag
00013 #define FAULT   0xff82          // fault address
00014 #define DEFERR  0xff84          // default error handler
00015 #define CMDPTR  0xff86          // command line tail
00016 #define SCRATCHPAD  0xff88      // Basic scratchpad area
00017 #define RESERVED    0xff9a      
00018 #define OSRDRM  0xffb9          // read byte in paged ROM
00019 #define MAINVDU 0xffbc          // main VDU character output entry point
00020 #define OSEVEN  0xffbf          // generate an event
00021 #define GSINIT  0xffc2          // general string input initialise routine
00022 #define GSREAD  0xffc5          // read character from string input
00023 #define UKCMD   0xffc9          // unknown command
00024 #define OSFSC   0xffcb          // filing system control
00025 #define OSFIND  0xffce          // open or close a file
00026 #define OSGBPB  0xffd1          // multiple byte access
00027 #define OSBPUT  0xffd4          // put a byte to a file
00028 #define OSBGET  0xffd7          // get a byte from a file
00029 #define OSARGS  0xffda          // read or set file arguments
00030 #define OSFILE  0xffdd          // load or save a file
00031 #define OSRDCH  0xffe0          // input a character
00032 #define OSASCI  0xffe3          // print a character with CR converted to LF, CR
00033 #define OSNEWL  0xffe7          // print a LF, CR sequence
00034 #define OSWRCH  0xffee          // print a character
00035 #define OSWORD  0xfff1          // do an OSWORD call
00036 #define OSBYTE  0xfff4          // do an OSBYTE call
00037 #define OSCLI   0xfff7          // interpret a command
00038 #define BRKV    0xfffa          // FAULT vector
00039 
00040 // default CP/M ram pages
00041 #define RAMSIZE (word)0x4000    // 16K ram
00042 #define RAMSTART 0x34ee
00043 #define RAMEND   RAMSTART+RAMSIZE
00044 #define PAGE     0x3800
00045 
00046 // the emulated ram space
00047 volatile unsigned char ram[RAMSIZE];
00048 
00049 // ramtop space with vectors
00050 volatile unsigned char ramtop[0x80];
00051 
00052 
00053 // read from memory space
00054 unsigned char rdmem(word addr) {
00055     extern volatile unsigned short pc;
00056  
00057      // all rom space
00058     if (addr<RAMSTART) {
00059         return rom[addr];
00060     }
00061 
00062     // ramtop with vectors
00063     if ((addr >=0xff80) && (addr <=0xffff)) {
00064         return ramtop[addr-0xff80];
00065     }
00066 
00067     // relocate $3400
00068     if ((addr >= RAMSTART) && (addr < RAMEND)) {
00069         return ram[addr-0x34ee];
00070     }
00071     return 0xff;   // non existant memory reads as 0xff
00072 }
00073 
00074 // write to memory space
00075 void wrmem (word addr, byte val) {
00076     extern volatile unsigned short pc;
00077 
00078     // memtop vector space
00079     if ((addr >=0xff80) && (addr <=0xffff)) {
00080         ramtop[addr-0xff80]=val;
00081         return;
00082     }
00083     // printf("MEMW %04x %02x\n\r",addr,val);
00084     if ((addr >= RAMSTART) && (addr < RAMEND)) {
00085         ram[addr-RAMSTART] = val;
00086     } 
00087 }
00088 
00089 // write a byte to IO space
00090 void out(unsigned char addr, unsigned char val) {
00091     printf("IO out called %02d, %02d\n\r",addr,val);
00092 }
00093 
00094 // read a byte from IO space
00095 unsigned char in(unsigned char addr) {
00096     printf("IO in called %02d\n\r",addr);
00097     return 0xff;
00098 }
00099