*

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+AllowShortBlocksOnASingleLine: Empty
+AllowShortCaseLabelsOnASingleLine: true
+AllowShortIfStatementsOnASingleLine: false
+AllowShortLoopsOnASingleLine: false
+AlwaysBreakAfterDefinitionReturnType: TopLevel
+BinPackArguments: false
+BinPackParameters: false
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.gitignore

@@ -0,0 +1,6 @@
+.DS*
+*jpg~
+*png~
+*gif~
+*bmp~
+uxn

README.md

@@ -7,3 +7,52 @@ A stack-based VM, written in ANSI C.
 ```
 cc uxn.c -std=c89 -Os -DNDEBUG -g0 -s -Wall -Wno-unknown-pragmas -o uxn
 ```
+
+## OP Codes
+
+```
+VALUE       OPCODE  EXPLANATION
+0x00000000  NOP     do nothing
+0x00000001  ADD     pop a, pop b, push a + b
+0x00000002  SUB     pop a, pop b, push a - b
+0x00000003  AND     pop a, pop b, push a & b
+0x00000004  OR      pop a, pop b, push a | b
+0x00000005  XOR     pop a, pop b, push a ^ b
+0x00000006  NOT     pop a, push !a
+0x00000007  IN      read one byte from stdin, push as word on stack
+0x00000008  OUT     pop one word and write to stream as one byte
+0x00000009  LOAD    pop a, push word read from address a
+0x0000000A  STOR    pop a, pop b, write b to address a
+0x0000000B  JMP     pop a, goto a
+0x0000000C  JZ      pop a, pop b, if a == 0 goto b
+0x0000000D  PUSH    push next word
+0x0000000E  DUP     duplicate word on stack
+0x0000000F  SWAP    swap top two words on stack
+0x00000010  ROL3    rotate top three words on stack once left, (a b c) -> (b c a)
+0x00000011  OUTNUM  pop one word and write to stream as number
+0x00000012  JNZ     pop a, pop b, if a != 0 goto b
+0x00000013  DROP    remove top of stack
+0x00000014  PUSHIP  push a in IP stack
+0x00000015  POPIP   pop IP stack to current IP, effectively performing a jump
+0x00000016  DROPIP  pop IP, but do not jump
+0x00000017  COMPL   pop a, push the complement of a
+```
+
+## Design
+
+### CPU
+
+- Build stack with pointer
+- Print stack
+- Build memory
+
+### PPU
+
+### Assembler
+
+
+### Emulator
+
+- SDL Layer
+
+### Assembly

uxn.c

@@ -11,9 +11,28 @@ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 WITH REGARD TO THIS SOFTWARE.
 */
 
+typedef unsigned char Uint8;
+#define STACK_DEPTH 256
+
+Uint8 data[STACK_DEPTH];
+Uint8 address[STACK_DEPTH];
+
+void
+stackprint(Uint8 *stack)
+{
+	int i;
+	for(i = 0; i < STACK_DEPTH; ++i) {
+		if(i % 16 == 0)
+			printf("\n");
+		printf("%02x ", stack[i]);
+	}
+	printf("\n");
+}
+
 int
 main(int argc, char *argv[])
 {
 	printf("hello\n");
+	stackprint(data);
 	return 0;
 }