A project to implement a console using the Mbed using VGA for video output and a PS/2 keyboard for the input. The eventual goal is to also include tools for managing SD cards, and a semi-self-hosting programming environment.
Dependencies: PS2_MbedConsole fastlib SDFileSystem vga640x480g_mbedconsole lightvm mbed
MbedConsole is a cool little project to have a self-contained computer all on an Mbed. So far it has VGA and PS/2 support and can stand alone without a computer powering it. Next planned features are SD card support and a lightweight programmable VM complete with a file editor and self-hosted assembler.
You can view additional details about it at http://earlz.net/tags/mbedconsole
forth_machine.cpp
- Committer:
- earlz
- Date:
- 2012-09-21
- Revision:
- 6:a4dff59ef214
- Child:
- 7:2ac6752d47d2
File content as of revision 6:a4dff59ef214:
#include "mbedconsole.h" #include "plEarlz.h" #include <stdint.h> #include <stdarg.h> //An extremely simple virtual machine to make this implementation about 10 times easier and probably a bit faster int pl_stackpos=0; int pl_stack[MAXSTACK]; int pl_dictionary_count=0; int pl_dictionary_size=0; WordKey *pl_dictionary; //todo: a hash table would be much faster void pl_push(int val) { if(pl_stackpos>=MAXSTACK) { vputs("Stack overflow!"); pl_error=StackOverflow; return; } pl_stack[pl_stackpos]=val; pl_stackpos++; } int pl_pop() { if(pl_stackpos<=0) { vputs("Stack underflow!"); pl_error=StackUnderflow; return 0; } pl_stackpos--; return pl_stack[pl_stackpos]; } WordKey *pl_lookup(char* name) { for(int i=0;i<pl_dictionary_count;i++) { if(strlcmp(name, pl_dictionary[i].name, 12)==0) { return &pl_dictionary[i]; } } return NULL; } int pl_addword() { if(pl_dictionary_size==0){ pl_dictionary=(WordKey*)malloc(sizeof(WordKey)*12); pl_dictionary_size=12; return 0; } if(pl_dictionary_size<=pl_dictionary_count) { void* tmp=realloc(pl_dictionary, pl_dictionary_size+sizeof(WordKey)*DICTIONARYSTEP); if(tmp==NULL) { vputs("Out of memory!! Epic Fail!!"); return -1; } pl_dictionary=(WordKey*)tmp; pl_dictionary_size+=sizeof(WordKey)*DICTIONARYSTEP; } return pl_dictionary_count++; } int forth_execute(uint8_t* block, int length) { int pos=0; while(pos<length) { Opcode op=(Opcode)block[pos]; //printf("opcode: %x\n",(int)op); switch(op) { case BranchTrue: if(pl_pop()){ pos++; pos=*((uint16_t*)&block[pos]); }else{ pos+=3; } break; case BranchFalse: if(!pl_pop()){ pos++; pos=*((uint16_t*)&block[pos]); }else{ pos+=3; } break; case Branch: pos++; pos=*((uint16_t*)&block[pos]); break; case Push: pos++; pl_push(*(uint32_t*)&block[pos]); pos+=4; break; case Pop: pos++; pl_pop(); break; case Add: pos++; pl_push(pl_pop()+pl_pop()); break; case Sub: pos++; pl_push(pl_pop()-pl_pop()); break; case Mul: pos++; pl_push(pl_pop()*pl_pop()); break; case Div: pos++; pl_push(pl_pop()/pl_pop()); break; case Mod: pos++; pl_push(pl_pop()%pl_pop()); break; case CallInt: pos++; uint32_t tmp=*(uint32_t*)&block[pos]; ((BuiltinFunction)tmp)(); pos+=4; break; default: vputs("Unknown opcode!!"); return; } } return 0; }