From 4693ae1c1c0c93922c9aaac774f3818cf01a2856 Mon Sep 17 00:00:00 2001
From: neauoire <aliceffekt@gmail.com>
Date: Thu, 11 Feb 2021 18:48:45 -0800
Subject: [PATCH] Added lineRect subroutine

---
 README.md         | 24 ++++++++++++++++++++++++
 emulator.c        | 11 ++++++-----
 examples/draw.usm | 30 ++++++++++++++++++++++++++++--
 uxn.c             |  2 --
 4 files changed, 58 insertions(+), 9 deletions(-)

diff --git a/README.md b/README.md
index 284d4e5..38fef20 100644
--- a/README.md
+++ b/README.md
@@ -2,6 +2,26 @@
 
 A [stack-based VM](https://wiki.xxiivv.com/site/uxn.html), written in ANSI C.
 
+## Setup
+
+If you wish to build your own emulator, you can create a new instance of Uxn like:
+
+```
+#include "uxn.h"
+
+Uxn u;
+
+if(!bootuxn(&u))
+	return error("Boot", "Failed");
+if(!loaduxn(&u, argv[1]))
+	return error("Load", "Failed");
+if(!init())
+	return error("Init", "Failed");
+
+evaluxn(u, u->vreset); /* Once on start */
+evaluxn(u, u->vframe); /* Each frame
+```
+
 ## Assembly Syntax
 
 ### Write
@@ -67,6 +87,10 @@ BRK
 - Auto-advance ldr?
 - Getting rid of IOR/IOW would be nice..
 - Sending from the wst to the rst, balance mode/flag?
+- Device that works like an extra memory bank
+- Line routine
+- LineRect routine
+- Draw a chr sprite.
 
 ## Refs
 
diff --git a/emulator.c b/emulator.c
index 8af7366..876ac09 100644
--- a/emulator.c
+++ b/emulator.c
@@ -190,6 +190,12 @@ consolew(Device *d, Uint8 b)
 Uint8
 screenr(Device *d, Uint8 b)
 {
+	switch(b) {
+	case 0: return (WIDTH >> 8) & 0xff;
+	case 1: return WIDTH & 0xff;
+	case 2: return (HEIGHT >> 8) & 0xff;
+	case 3: return HEIGHT & 0xff;
+	}
 	return d->mem[b];
 }
 
@@ -293,11 +299,6 @@ main(int argc, char **argv)
 	devmouse = portuxn(&u, "mouse", mouser, mousew);
 	devkey = portuxn(&u, "key", keyr, keyw);
 
-	devscreen->mem[0] = (WIDTH >> 8) & 0xff;
-	devscreen->mem[1] = WIDTH & 0xff;
-	devscreen->mem[2] = (HEIGHT >> 8) & 0xff;
-	devscreen->mem[3] = HEIGHT & 0xff;
-
 	start(&u);
 
 	echos(&u.wst, 0x40, "stack");
diff --git a/examples/draw.usm b/examples/draw.usm
index a79302f..5b1387a 100644
--- a/examples/draw.usm
+++ b/examples/draw.usm
@@ -22,11 +22,22 @@
 	( fill rect x y w h )
 	,0040 ,0040 ,0060 ,0040 ,fillrect JSR
 
-
 	,01 ,color STR
 	( fill rect x y w h )
 	,00a0 ,0010 ,0020 ,0020 ,fillrect JSR
 
+	,02 ,color STR
+	( fill rect x y w h )
+	,00b0 ,0040 ,0020 ,0020 ,linerect JSR
+
+	,03 ,color STR
+	( fill rect x y w h )
+	,0058 ,0028 ,0050 ,0050 ,linerect JSR
+
+	,01 ,color STR
+	( fill rect x y w h )
+	,0028 ,0038 ,0050 ,0030 ,linerect JSR
+
 	,redraw JSR
 
 BRK
@@ -37,13 +48,28 @@ BRK
 	@fillrectrow
 		,x LDR^ ,x_ STR^
 		@fillrectcol
-			,x_ LDR^ ,y_ LDR^ ,putpixel JSR
+			( draw ) ,x_ LDR^ ,y_ LDR^ ,putpixel JSR
 			,x_ LDR^ ,0001 ADD^ ,x_ STR^ 
 			,x_ LDR^ ,w LDR^ ,x LDR^ ADD^ LTH^ ,fillrectcol ROT JMP? POP^
 		,y_ LDR^ ,0001 ADD^ ,y_ STR^ 
 		,y_ LDR^ ,h LDR^ ,y LDR^ ADD^ LTH^ ,fillrectrow ROT JMP? POP^
 	RTS
 
+@linerect
+	,h STR^ ,w STR^ ,y STR^ ,x STR^
+	,x LDR^ ,x_ STR^ ,y LDR^ ,y_ STR^
+	@linerectcol
+		( draw ) ,x LDR^ ,y_ LDR^ ,putpixel JSR
+		( draw ) ,x LDR^ ,w LDR^ ADD^ ,y_ LDR^ ,putpixel JSR
+		,y_ LDR^ ,0001 ADD^ ,y_ STR^ 
+		,y_ LDR^ ,h LDR^ ,y LDR^ ADD^ LTH^ ,linerectcol ROT JMP? POP^
+	@linerectrow
+		( draw ) ,x_ LDR^ ,y LDR^ ,putpixel JSR
+		( draw ) ,x_ LDR^ ,y LDR^ ,h LDR^ ADD^ ,putpixel JSR
+		,x_ LDR^ ,0001 ADD^ ,x_ STR^ 
+		,x_ LDR^ ,w LDR^ ,x LDR^ ADD^ ,0001 ADD^ LTH^ ,linerectrow ROT JMP? POP^
+	RTS
+
 @redraw
 	,0000 IOW^
 	,0000 IOW^
diff --git a/uxn.c b/uxn.c
index 7f1520a..b55571b 100644
--- a/uxn.c
+++ b/uxn.c
@@ -199,8 +199,6 @@ loaduxn(Uxn *u, char *filepath)
 	return 1;
 }
 
-/* to start: evaluxn(u, u->vreset); */
-
 Device *
 portuxn(Uxn *u, char *name, Uint8 (*rfn)(Device *, Uint8), Uint8 (*wfn)(Device *, Uint8))
 {