Jordan Earls
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
Diff: forth_machine.cpp
- Revision:
- 6:a4dff59ef214
- Child:
- 7:2ac6752d47d2
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/forth_machine.cpp Fri Sep 21 04:53:45 2012 +0000
@@ -0,0 +1,154 @@
+#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;
+}
\ No newline at end of file