From cdde55f54a0880bde5694fcdea8e386ada0cd5ce Mon Sep 17 00:00:00 2001
From: Joshua Wise <joshua@rebirth.joshuawise.com>
Date: Sat, 13 Dec 2008 19:50:39 -0500
Subject: [PATCH] Add a first cut at text.

---
 aseg-paging/Makefile   |  1 +
 aseg-paging/firstrun.c |  4 ++
 include/fb.h           |  1 +
 include/text.h         |  9 ++++
 video/text.c           | 95 ++++++++++++++++++++++++++++++++++++++++++
 video/tnt2.c           |  5 ++-
 6 files changed, 113 insertions(+), 2 deletions(-)
 create mode 100644 include/text.h
 create mode 100644 video/text.c

diff --git a/aseg-paging/Makefile b/aseg-paging/Makefile
index 73d7feb..1eeee83 100644
--- a/aseg-paging/Makefile
+++ b/aseg-paging/Makefile
@@ -47,6 +47,7 @@ OBJS =	../ich2/smi.o \
 	../video/tnt2.o \
 	../video/fb.o \
 	../video/checksumrect.o \
+	../video/text.o \
 	drivers.o \
 	../lib/minilib.o \
 	../lib/doprnt.o \
diff --git a/aseg-paging/firstrun.c b/aseg-paging/firstrun.c
index 48a1ac0..0233a7c 100644
--- a/aseg-paging/firstrun.c
+++ b/aseg-paging/firstrun.c
@@ -5,6 +5,7 @@
 #include <output.h>
 #include "vga-overlay.h"
 #include <smram.h>
+#include <text.h>
 #include "../net/net.h"
 
 extern int _bss, _bssend;
@@ -43,6 +44,9 @@ void smi_init() {
 			output("Found a card");
 	}
 	outputf("Driver probe complete");
+	
+	/* Load in fonts. */
+	text_init();
 
 	smi_register_handler(SMI_EVENT_FAST_TIMER, timer_handler);
 	smi_enable_event(SMI_EVENT_FAST_TIMER);
diff --git a/include/fb.h b/include/fb.h
index 19dae0b..dd86894 100644
--- a/include/fb.h
+++ b/include/fb.h
@@ -21,6 +21,7 @@ struct vmode {
 
 struct fbdevice {
 	unsigned char *fbaddr;
+	unsigned char *textbase;	/* A safe place to put a textfb. */
 	void *priv;
 	getvmode_t getvmode;
 	checksum_rect_t checksum_rect;
diff --git a/include/text.h b/include/text.h
new file mode 100644
index 0000000..9506d40
--- /dev/null
+++ b/include/text.h
@@ -0,0 +1,9 @@
+#ifndef _TEXT_H
+
+#include <stdint.h>
+
+extern void text_init();
+extern void text_render(unsigned char *buf, unsigned int x, unsigned int y, unsigned int w, unsigned int h);
+extern uint32_t text_checksum(int x, int y, int w, int h);
+
+#endif
diff --git a/video/text.c b/video/text.c
new file mode 100644
index 0000000..c9068b9
--- /dev/null
+++ b/video/text.c
@@ -0,0 +1,95 @@
+#include <io.h>
+#include <text.h>
+#include <paging.h>
+#include <minilib.h>
+#include <stdint.h>
+
+static unsigned char _font[256 * 32];
+
+/* Must be called from a firstrun context, where we don't care about saving
+ * 0x3CE state. */
+void text_init()
+{
+	unsigned char oldread;
+	outb(0x3CE, 0x05 /* Mode register */);
+	outb(0x3CF, inb(0x3CF) & ~(0x10 /* Odd/even */));
+	outb(0x3CE, 0x04 /* Read register */);
+	oldread = inb(0x3CF);
+	outb(0x3CF, 0x02 /* Font plane */);
+	memcpy(_font, p2v(0xB8000), sizeof(_font));
+	outb(0x3CF, oldread);
+}
+
+void text_render(unsigned char *buf, unsigned int x, unsigned int y, unsigned int w, unsigned int h)
+{
+	unsigned char *video = p2v(0xB8000);
+	unsigned int textx = x / 9;
+	unsigned int texty = y / 14;
+	unsigned int cx, cy;
+	unsigned char ch, at, font;
+	
+	for (cy = y; cy < (y + h); cy++)
+	{
+		texty = cy / 14;
+		textx = cx / 9;
+		ch = video[texty * 50 + textx * 2];
+		at = video[texty * 50 + textx * 2 + 1];
+		font = _font[ch * 32 + cy % 14];
+		for (cx = x; cx < (x + w); cx++)
+		{
+			unsigned int pos = cx % 9;
+			if (pos == 0)
+			{
+				textx = cx / 9;
+				ch = video[texty * 50 + textx * 2];
+				at = video[texty * 50 + textx * 2 + 1];
+				font = _font[ch * 32 + cy % 14];
+			}
+			/* XXX always BGR888 */
+			if (pos == 8)	/* 9th pixel is cloned */
+				pos = 7;
+			if ((font >> (7 - pos)) & 1)
+			{
+				*(buf++) = (at & 0x01) ? 0xFF : 0x00;
+				*(buf++) = (at & 0x02) ? 0xFF : 0x00;
+				*(buf++) = (at & 0x04) ? 0xFF : 0x00;
+			} else {
+				*(buf++) = (at & 0x10) ? 0xFF : 0x00;
+				*(buf++) = (at & 0x20) ? 0xFF : 0x00;
+				*(buf++) = (at & 0x40) ? 0xFF : 0x00;
+			}
+		}
+	}
+}
+
+uint32_t text_checksum(int x, int y, int w, int h)
+{
+	unsigned char *video = p2v(0xB8000);
+	unsigned int textx = x / 9;
+	unsigned int texty = y / 14;
+	int cx, cy;
+	unsigned char ch, at;
+	uint32_t cksm = 0;
+	
+	for (cy = y; cy < (y + h); cy++)
+	{
+		texty = cy / 14;
+		textx = cx / 9;
+		ch = video[texty * 50 + textx * 2];
+		at = video[texty * 50 + textx * 2 + 1];
+		for (cx = x; cx < (x + w); cx++)
+		{
+			unsigned int pos = cx % 9;
+			if (pos == 0)
+			{
+				textx = cx / 9;
+				ch = video[texty * 50 + textx * 2];
+				at = video[texty * 50 + textx * 2 + 1];
+			}
+			
+			cksm += ch + (at << 16);
+		}
+	}
+	
+	return cksm;
+}
diff --git a/video/tnt2.c b/video/tnt2.c
index c79912c..f23a9d7 100644
--- a/video/tnt2.c
+++ b/video/tnt2.c
@@ -4,6 +4,7 @@
 #include <output.h>
 #include <fb.h>
 #include <paging.h>
+#include <text.h>
 
 #include "checksumrect.h"
 
@@ -33,11 +34,11 @@ static void tnt2_getvmode(void *priv)
 		break;
 	case 0:
 		tnt2_fb.curmode.text = 1;
-		tnt2_fb.checksum_rect = (checksum_rect_t) 0;
+		tnt2_fb.checksum_rect = (checksum_rect_t) text_checksum;
 		break;
 	default:
 		tnt2_fb.curmode.text = 1;
-		tnt2_fb.checksum_rect = (checksum_rect_t) 0;
+		tnt2_fb.checksum_rect = (checksum_rect_t) text_checksum;
 		outputf("Unknown TNT2 format %x", vgard(0x28));
 		break;
 	}
-- 
2.43.0