collapseos/tools/emul/shell.c

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#include <stdint.h>
#include <stdio.h>
#include <termios.h>
#include "libz80/z80.h"
#include "shell-kernel.h"
/* Collapse OS shell with filesystem
*
* On startup, if "cfsin" directory exists, it packs it as a afke block device
* and loads it in. Upon halting, unpcks the contents of that block device in
* "cfsout" directory.
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*
* Memory layout:
*
* 0x0000 - 0x3fff: ROM code from shell.asm
* 0x4000 - 0x4fff: Kernel memory
* 0x5000 - 0xffff: Userspace
*
* I/O Ports:
*
* 0 - stdin / stdout
* 1 - Filesystem blockdev data read/write. Reading and writing to it advances
* the pointer.
* 2 - Filesystem blockdev seek / tell. Low byte
* 3 - Filesystem blockdev seek / tell. High byte
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*/
// in sync with shell.asm
#define RAMSTART 0x4000
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#define STDIO_PORT 0x00
#define FS_DATA_PORT 0x01
#define FS_SEEKL_PORT 0x02
#define FS_SEEKH_PORT 0x03
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static Z80Context cpu;
static uint8_t mem[0xffff] = {0};
static uint8_t fsdev[0xffff] = {0};
static uint16_t fsdev_size = 0;
static uint16_t fsdev_ptr = 0;
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static int running;
static uint8_t io_read(int unused, uint16_t addr)
{
addr &= 0xff;
if (addr == STDIO_PORT) {
uint8_t c = getchar();
if (c == EOF) {
running = 0;
}
return c;
} else if (addr == FS_DATA_PORT) {
if (fsdev_ptr < fsdev_size) {
return fsdev[fsdev_ptr++];
} else {
return 0;
}
} else if (addr == FS_SEEKL_PORT) {
return fsdev_ptr & 0xff;
} else if (addr == FS_SEEKH_PORT) {
return fsdev_ptr >> 8;
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} else {
fprintf(stderr, "Out of bounds I/O read: %d\n", addr);
return 0;
}
}
static void io_write(int unused, uint16_t addr, uint8_t val)
{
addr &= 0xff;
if (addr == STDIO_PORT) {
if (val == 0x04) { // CTRL+D
running = 0;
} else {
putchar(val);
}
} else if (addr == FS_DATA_PORT) {
if (fsdev_ptr < fsdev_size) {
fsdev[fsdev_ptr++] = val;
}
} else if (addr == FS_SEEKL_PORT) {
fsdev_ptr = (fsdev_ptr & 0xff00) | val;
} else if (addr == FS_SEEKH_PORT) {
fsdev_ptr = (fsdev_ptr & 0x00ff) | (val << 8);
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} else {
fprintf(stderr, "Out of bounds I/O write: %d / %d\n", addr, val);
}
}
static uint8_t mem_read(int unused, uint16_t addr)
{
return mem[addr];
}
static void mem_write(int unused, uint16_t addr, uint8_t val)
{
if (addr < RAMSTART) {
fprintf(stderr, "Writing to ROM (%d)!\n", addr);
}
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mem[addr] = val;
}
int main()
{
// Setup fs blockdev
FILE *fp = popen("../cfspack/cfspack cfsin", "r");
if (fp != NULL) {
printf("Initializing filesystem\n");
int i = 0;
int c = fgetc(fp);
while (c != EOF) {
fsdev[i] = c & 0xff;
i++;
c = fgetc(fp);
}
fsdev_size = i;
pclose(fp);
} else {
printf("Can't initialize filesystem. Leaving blank.\n");
}
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// Turn echo off: the shell takes care of its own echoing.
struct termios termInfo;
if (tcgetattr(0, &termInfo) == -1) {
printf("Can't setup terminal.\n");
return 1;
}
termInfo.c_lflag &= ~ECHO;
termInfo.c_lflag &= ~ICANON;
tcsetattr(0, TCSAFLUSH, &termInfo);
// initialize memory
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for (int i=0; i<sizeof(KERNEL); i++) {
mem[i] = KERNEL[i];
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}
// Run!
running = 1;
Z80RESET(&cpu);
cpu.ioRead = io_read;
cpu.ioWrite = io_write;
cpu.memRead = mem_read;
cpu.memWrite = mem_write;
while (running) {
Z80Execute(&cpu);
}
printf("Done!\n");
termInfo.c_lflag |= ECHO;
termInfo.c_lflag |= ICANON;
tcsetattr(0, TCSAFLUSH, &termInfo);
return 0;
}