From c861cdf62958e103a42b8e506c2031e35ea5af50 Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Thu, 30 Dec 1993 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1993-12-30

---
 carrera/mem.h    |  1 +
 carrera/screen.c | 43 ++++++++++++++++++++++++++++++++++++-------
 pc/devvga.c      | 30 +++++++++++++++++++++++++-----
 pc/mem.h         |  1 +
 4 files changed, 63 insertions(+), 12 deletions(-)

diff --git a/carrera/mem.h b/carrera/mem.h
index e5edb6455718b221c9b0b5b5fcd662b210e35c7f..b7bc7e976cd6883fa47d80d1be1d52bb7a712120 100644
--- a/carrera/mem.h
+++ b/carrera/mem.h
@@ -160,6 +160,7 @@
 #define	KZERO	KSEG0			/* base of kernel address space */
 #define	KTZERO	(KZERO+0x20000)		/* first address in kernel text */
 #define	USTKSIZE	(4*1024*1024)	/* size of user stack */
+#define globalmem(x)	(((ulong)x)&KZERO)	/* addresses valid in all contexts */
 /*
  * Exception codes
  */
diff --git a/carrera/screen.c b/carrera/screen.c
index 672ef9043dbb4304d988e368ca43d2b6b86a8ef0..8d89ff80df1c763f388e68b15da7a733c291bc01 100644
--- a/carrera/screen.c
+++ b/carrera/screen.c
@@ -172,14 +172,14 @@ screeninit(void)
 {
 	int i, x;
 
+	gscreen.ldepth = 0;
+
 	setmode(&dfltmode);
 
-	gscreen.ldepth = 3;
 	for(i = 0; i < 16; i++){
 		x = x6to32((i*63)/15);
 		setcolor(i, x, x, x);
 	}
-	gscreen.ldepth = 0;
 
 	/* allocate a new soft bitmap area */
 	gscreen.base = xalloc(1024*1024);
@@ -303,7 +303,18 @@ screenputs(char *s, int n)
 void
 getcolor(ulong p, ulong *pr, ulong *pg, ulong *pb)
 {
-	p &= (1<<(1<<gscreen.ldepth))-1;
+	ulong x;
+
+	switch(gscreen.ldepth){
+	default:
+		x = 0xf;
+		break;
+	case 3:
+		x = 0xff;
+		break;
+	}
+	p &= x;
+	p ^= x;
 	*pr = colormap[p][0];
 	*pg = colormap[p][1];
 	*pb = colormap[p][2];
@@ -312,7 +323,18 @@ getcolor(ulong p, ulong *pr, ulong *pg, ulong *pb)
 int
 setcolor(ulong p, ulong r, ulong g, ulong b)
 {
-	p &= (1<<(1<<gscreen.ldepth))-1;
+	ulong x;
+
+	switch(gscreen.ldepth){
+	default:
+		x = 0xf;
+		break;
+	case 3:
+		x = 0xff;
+		break;
+	}
+	p &= x;
+	p ^= x;
 	colormap[p][0] = r;
 	colormap[p][1] = g;
 	colormap[p][2] = b;
@@ -442,7 +464,14 @@ setmode(VGAmode *v)
 	for(i = 0; i < sizeof(v->attribute); i++)
 		arout(i, v->attribute[i]);
 
-	EISAOUTB(0x3C6, 0x0F);	/* pel mask */
+	switch(gscreen.ldepth){
+	case 3:
+		EISAOUTB(0x3C6, 0xFF);	/* pel mask */
+		break;
+	default:
+		EISAOUTB(0x3C6, 0x0F);	/* pel mask */
+		break;
+	}
 	EISAOUTB(0x3C8, 0x00);	/* pel write address */
 
 	EISAOUTB(0x3bf, 0x03);	/* hercules compatibility reg */
@@ -522,8 +551,8 @@ screenupdate(void)
 		for(i = 0; i < len; i += 8) {
 			s = (ulong*)(sp+i);
 			h = (ulong*)(hp+i);
-			in1 = ~s[0];
-			in2 = ~s[1];
+			in1 = s[0];
+			in2 = s[1];
 			h[0] = swiz(in2);
 			h[1] = swiz(in1);
 		}
diff --git a/pc/devvga.c b/pc/devvga.c
index 1e2c61c9cdd17db9939a9dd8de20e0e5d3621749..411fe3d32945ddc8d403457ef695c8d550b7f271 100644
--- a/pc/devvga.c
+++ b/pc/devvga.c
@@ -471,12 +471,10 @@ setscreen(int maxx, int maxy, int ldepth)
 	case 2:
 	case 1:
 	case 0:
-		gscreen.ldepth = 3;
 		for(i = 0; i < 16; i++){
 			x = x6to32((i*63)/15);
 			setcolor(i, x, x, x);
 		}
-		gscreen.ldepth = ldepth;
 		break;
 	}
 	cga = 0;
@@ -608,7 +606,7 @@ screenupdate(void)
 	switch(gscreen.ldepth){
 	case 0:
 		r.min.x &= ~15;		/* 16 pixel alignment for l0update() */
-		f = l0update;
+		f = memmove;
 		len = (r.max.x + 7)/8 - r.min.x/8;
 		if(len & 1)
 			len++;		/* 16 bit alignment for l0update() */
@@ -1071,7 +1069,18 @@ screenbits(void)
 void
 getcolor(ulong p, ulong *pr, ulong *pg, ulong *pb)
 {
-	p &= (1<<(1<<gscreen.ldepth))-1;
+	ulong x;
+
+	switch(gscreen.ldepth){
+	default:
+		x = 0xf;
+		break;
+	case 3:
+		x = 0xff;
+		break;
+	}
+	p &= x;
+	p ^= x;
 	lock(&screenlock);
 	*pr = colormap[p][0];
 	*pg = colormap[p][1];
@@ -1082,7 +1091,18 @@ getcolor(ulong p, ulong *pr, ulong *pg, ulong *pb)
 int
 setcolor(ulong p, ulong r, ulong g, ulong b)
 {
-	p &= (1<<(1<<gscreen.ldepth))-1;
+	ulong x;
+
+	switch(gscreen.ldepth){
+	default:
+		x = 0xf;
+		break;
+	case 3:
+		x = 0xff;
+		break;
+	}
+	p &= x;
+	p ^= x;
 	lock(&screenlock);
 	colormap[p][0] = r;
 	colormap[p][1] = g;
diff --git a/pc/mem.h b/pc/mem.h
index 25c3b4dd722acf5688fe2f306b03d9607691fc4f..3b4faee802a5cb9138e2ba0cf0ad49444adea820 100644
--- a/pc/mem.h
+++ b/pc/mem.h
@@ -49,6 +49,7 @@
 #define KSTACK		4096			/* Size of kernel stack */
 #define ROMBIOS		(KZERO|0xF0000)
 #define	ISAMEMSIZE	(4*MB)			/* mem space reserved for ISA */
+#define globalmem(x)	(((ulong)x)&KZERO)	/* addresses valid in all contexts */
 
 #define	MACHSIZE	4096