Added constants

README.md

@@ -12,18 +12,19 @@ cc uxn.c -std=c89 -Os -DNDEBUG -g0 -s -Wall -Wno-unknown-pragmas -o uxn
 
 ### Write
 
-- `;variable`, set a name to address on the zero-page
-- `:label`, set a name to an address
+- `;variable`, set a label to an assigned address
+- `:const`, set a label to a constant short
+- `@label`, set a label to an address
 
 ### Read
 
-- `,literal`, get a literal pointer
-- `.pointer`, get a raw pointer
+- `,literal`, push label value to stack
+- `.pointer`, read label value
 
 ### Special
 
-- `@0010`, move to position in the program
-- `( comment )`
+- `( comment )`, toggle parsing on/off
+- `|0010`, move to position in the program
 
 ```
 ;value ( alloc a zero-page variable )
@@ -49,7 +50,6 @@ cc uxn.c -std=c89 -Os -DNDEBUG -g0 -s -Wall -Wno-unknown-pragmas -o uxn
 ### Assembler
 
 - Catch overflow/underflow
-- Constants
 - Jumps should be relative
 
 ### CPU
@@ -63,6 +63,10 @@ cc uxn.c -std=c89 -Os -DNDEBUG -g0 -s -Wall -Wno-unknown-pragmas -o uxn
 - Build PPU
 - Add flags..
 
+### Devices
+
+- Devices each have an input byte, an output byte and two request bytes.
+
 ## Refs
 
 https://code.9front.org/hg/plan9front/file/a7f9946e238f/sys/src/games/nes/cpu.c

etc/usm.sublime-syntax

@@ -18,7 +18,7 @@ contexts:
     - include: strings
 
   numbers:
-    - match: '\@(\S+)\s?'
+    - match: '\|(\S+)\s?'
       scope: punctuation.definition
       pop: true
 
@@ -29,6 +29,9 @@ contexts:
     - match: '\;(\S+)\s?'
       scope: string.control
       pop: true
+    - match: '\_(\S+)\s?'
+      scope: string.control
+      pop: true
     - match: '\,(\S+)\s?'
       scope: keyword.control
       pop: true

examples/blank.usm

@@ -0,0 +1,27 @@
+( blank project )
+
+;variable1
+;variable2
+_constant1 abcd
+
+|0100 ( -------------------------------- )
+
+:RESET BRK
+
+|c000 ( -------------------------------- )
+
+:FRAME ( FRAME-START )
+
+
+
+BRK ( FRAME-END )
+
+|d000 ( -------------------------------- )
+
+:ERROR BRK
+
+|FFFA ( -------------------------------- )
+
+.RESET
+.FRAME
+.ERROR

examples/core.usm

@@ -1,27 +1,29 @@
-( define some variables in the zero-page )
+( blank project )
 
-;var1
-;var2
+;variable1
+:constant1 9abc
 
-@0100 
+|0100 ( -------------------------------- )
 
-:RESET ( --- )
-	,1234
-	BRK
+@RESET
 
-@c000 ( much further.. )
+,abcd
 
-:FRAME ( --- )
-	,ab ,0008 str
-	BRK
+BRK ( RESET-END )
 
-@d000 ( further still.. )
+|c000 ( -------------------------------- )
 
-:ERROR ( --- )
-	,cdef
-	BRK
+@FRAME ( FRAME-START )
 
-@FFFA ( vectors, last 3 shorts )
+,abcd
+
+BRK ( FRAME-END )
+
+|d000 ( -------------------------------- )
+
+@ERROR BRK
+
+|FFFA ( -------------------------------- )
 
 .RESET
 .FRAME

uxnasm.c

@@ -103,7 +103,7 @@ shex(char *s) /* string to num */
 		else if(c >= 'A' && c <= 'F')
 			n = n * 16 + 10 + (c - 'A');
 		else if(c >= 'a' && c <= 'f')
-			n = n * 16 + 10 + (c - 'f');
+			n = n * 16 + 10 + (c - 'a');
 	return n;
 }
 
@@ -190,6 +190,14 @@ makelabel(char *id, Uint16 addr)
 	return 1;
 }
 
+int
+makeconst(char *id, FILE *f)
+{
+	char wv[64];
+	fscanf(f, "%s", wv);
+	return makelabel(id, shex(wv));
+}
+
 int
 pass1(FILE *f)
 {
@@ -199,16 +207,22 @@ pass1(FILE *f)
 	while(fscanf(f, "%s", w) == 1) {
 		if(iscomment(w, &skip)) continue;
 		suca(w);
-		if(w[0] == ':' && !makelabel(w + 1, addr))
+		if(w[0] == '@' && !makelabel(w + 1, addr))
 			return error("Pass1 failed", w);
 		if(w[0] == ';' && !makelabel(w + 1, vars++))
 			return error("Pass1 failed", w);
+		if(w[0] == ':') {
+			if(!makeconst(w + 1, f))
+				return error("Pass1 failed", w);
+			else
+				continue;
+		}
 		/* move addr ptr */
 		if(findop(w) || scmp(w, "BRK"))
 			addr += 1;
-		else if(w[0] == '@') {
+		else if(w[0] == '|')
 			addr = shex(w + 1);
-		} else if(w[0] == ':')
+		else if(w[0] == '@')
 			addr += 0;
 		else if(w[0] == ';')
 			addr += 0;
@@ -233,12 +247,14 @@ pass2(FILE *f)
 	while(fscanf(f, "%s", w) == 1) {
 		Uint8 op = 0;
 		Label *l;
-		if(w[0] == ':') continue;
+		if(w[0] == '@') continue;
 		if(w[0] == ';') continue;
 		suca(w);
 		if(iscomment(w, &skip) || ismarker(w)) continue;
-		if(w[0] == '@')
+		if(w[0] == '|')
 			p.ptr = shex(w + 1);
+		else if(w[0] == ':')
+			fscanf(f, "%s", w);
 		else if((op = findop(w)) || scmp(w, "BRK"))
 			pushbyte(op, 0);
 		else if((l = findlabel(w + 1)))