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: plEarlz.cpp
- Revision:
- 7:2ac6752d47d2
- Parent:
- 6:a4dff59ef214
- Child:
- 8:f356684767ef
--- a/plEarlz.cpp Fri Sep 21 04:53:45 2012 +0000
+++ b/plEarlz.cpp Sat Sep 22 03:00:55 2012 +0000
@@ -25,6 +25,8 @@
+volatile BranchTarget *last_target=NULL;
+
ErrorType pl_error=None;
@@ -36,12 +38,11 @@
Quote
};
-
uint8_t *pl_codeblock;
int pl_blockpos;
int pl_blocksize;
-void push_opcode_byte(uint8_t val)
+uint8_t* push_opcode_byte(uint8_t val)
{
if(pl_blockpos>=pl_blocksize)
{
@@ -56,8 +57,9 @@
}
pl_codeblock[pl_blockpos]=val;
pl_blockpos++;
+ return &pl_codeblock[pl_blockpos-1];
}
-void push_opcode(Opcode val)
+Opcode* push_opcode(Opcode val)
{
if(pl_blockpos>=pl_blocksize)
{
@@ -72,8 +74,9 @@
}
pl_codeblock[pl_blockpos]=(uint8_t)val;
pl_blockpos++;
+ return (Opcode*)&pl_codeblock[pl_blockpos-1];
}
-void push_opcode_word(uint16_t val)
+uint16_t* push_opcode_word(uint16_t val)
{
if(pl_blockpos>=pl_blocksize)
{
@@ -88,8 +91,9 @@
}
*(uint16_t*)&pl_codeblock[pl_blockpos]=val;
pl_blockpos+=2;
+ return (uint16_t*)(&pl_codeblock[pl_blockpos-2]);
}
-void push_opcode_dword(uint32_t val)
+uint32_t* push_opcode_dword(uint32_t val)
{
if(pl_blockpos>=pl_blocksize)
{
@@ -104,6 +108,7 @@
}
*(uint32_t*)&pl_codeblock[pl_blockpos]=val;
pl_blockpos+=4;
+ return (uint32_t*)&pl_codeblock[pl_blockpos-4];
}
void new_codeblock(bool freeit)
{
@@ -114,11 +119,32 @@
pl_codeblock=(uint8_t*)malloc(CODEBLOCKSTEP);
pl_blockpos=0;
pl_blocksize=CODEBLOCKSTEP;
+ last_target=NULL;
}
int execute_codeblock()
{
return forth_execute(pl_codeblock, pl_blockpos);
}
+
+
+void push_target(uint16_t* address)
+{
+ volatile BranchTarget* target=(BranchTarget*)malloc(sizeof(BranchTarget));
+ target->previous=last_target;
+ target->target=address;
+ last_target=target;
+}
+void pop_target()
+{
+ if(last_target==NULL)
+ {
+ vputs("Unmatched control statement!\n");
+ return;
+ }
+ volatile void* tmp=last_target;
+ last_target=last_target->previous;
+ free((void*)tmp);
+}
int compile_word(char *word, WordType type) //returns 0 for success, 1 for ending word found, -1 for error
{
@@ -133,6 +159,7 @@
push_opcode_dword((uint32_t)&bi_print);
}else if(word[0]==';')
{
+ push_opcode(Ret);
//execute!
return 1;
}else if(word[0]=='+'){
@@ -148,9 +175,7 @@
}else if(word[0]=='*'){
push_opcode(Mul);
}else if(word[0]=='!'){
- int tmp=pl_pop();
- int* tmp2=(int*)pl_pop();
- *tmp2=tmp;
+ //push_opcode(Store);
}else if(word[0]=='?'){
pl_push(*(int*)pl_pop());
}else if(word[0]=='='){
@@ -162,12 +187,24 @@
}
}else if(strlcmp("if", word, 3)==0){
-
-
+ printf("if statement %x\r\n", pl_blockpos);
+ push_opcode(BranchFalse);
+ push_target(push_opcode_word(0));
+ }else if(strlcmp("else", word, 5)==0){
+ printf("else statement %x\r\n", pl_blockpos);
+ push_opcode(Branch);
+ uint16_t* tmp=push_opcode_word(0);
+ volatile uint16_t* tmp2=last_target->target;
+ *tmp2=pl_blockpos;
+ pop_target();
+ push_target(tmp); //have to do it after we pop it or we fall into an infinite loop!
+ }else if(strlcmp("end", word, 4)==0){
+ *(last_target->target)=pl_blockpos;
+ pop_target();
}else{
- vputs("I don't know the word ");
+ vputs("I don't know the word '");
vputs(word);
- vputs("\n");
+ vputs("'\n");
}
}
return 0;
@@ -233,6 +270,15 @@
int pl_shell()
{
+ uint8_t* tmpf[20];
+ push_target((uint16_t*)&tmpf[2]);
+ *last_target->target=50;
+ pop_target();
+ push_target((uint16_t*)&tmpf[4]);
+ *last_target->target=200;
+ pop_target();
+
+ printf("foo: %i %i\r\n", (int)*(uint16_t*)&tmpf[2], (int)*(uint16_t*)&tmpf[4]);
vputs(">>plEarlz -- A forth-ish shell<<\n");
printheapstats();
vputs("\n");