From 91fc6b749ad3a64c9a2686952eb30be517c6beb9 Mon Sep 17 00:00:00 2001
From: John Tsiombikas <nuclear@mutantstargoat.com>
Date: Fri, 27 Apr 2018 19:46:45 +0300
Subject: [PATCH] logohack exit on escape

---
 src/kmain.c     |   13 +++----------
 src/startup.s   |   22 ++++++++++++++--------
 src/video.c     |   30 ++++++++++++++++++++++++++++++
 src/video.h     |    9 +++++++++
 src/video_asm.s |   27 +++++++++++++++++++++++++++
 5 files changed, 83 insertions(+), 18 deletions(-)
 create mode 100644 src/video.c
 create mode 100644 src/video.h
 create mode 100644 src/video_asm.s

diff --git a/src/kmain.c b/src/kmain.c
index fab4e6f..0ffc152 100644
--- a/src/kmain.c
+++ b/src/kmain.c
@@ -23,16 +23,8 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #include "keyb.h"
 #include "timer.h"
 #include "contty.h"
-#include "int86.h"
+#include "video.h"
 
-static void set_mode13h(void)
-{
-	struct int86regs regs;
-
-	memset(&regs, 0, sizeof regs);
-	regs.eax = 0x13;
-	int86(0x10, &regs);
-}
 
 void logohack(void);
 
@@ -56,8 +48,9 @@ void pcboot_main(void)
 		halt_cpu();
 		while((c = kb_getkey()) >= 0) {
 			if(c >= KB_F1 && c <= KB_F12) {
-				set_mode13h();
+				set_vga_mode(0x13);
 				logohack();
+				set_vga_mode(3);
 			}
 			if(isprint(c)) {
 				printf("key: %d '%c'       \n", c, (char)c);
diff --git a/src/startup.s b/src/startup.s
index 8041c13..0a36b67 100644
--- a/src/startup.s
+++ b/src/startup.s
@@ -20,6 +20,8 @@
 	.extern _bss_start
 	.extern _bss_end
 	.extern pcboot_main
+	.extern wait_vsync
+	.extern kb_getkey
 
 	# move the stack to the top of the conventional memory
 	movl $0x80000, %esp
@@ -42,6 +44,8 @@ skip_bss_zero:
 
 	.global logohack
 logohack:
+	pusha
+
 	# copy palette
 	mov $logo_pal, %esi
 	xor %cl, %cl
@@ -131,16 +135,18 @@ xloop:
 
 	incl frameno
 
-	# wait vsync
-	mov $0x3da, %dx
-0:	in %dx, %al
-	and $8, %al
-	jnz 0b
-0:	in %dx, %al
-	and $8, %al
-	jz 0b
+	call wait_vsync
+
+	# check for escape keypress
+	call kb_getkey
+	cmp $27, %eax
+	jz 0f
+
 	jmp frameloop
 
+0:	popa
+	ret
+
 xval: .long 0
 yval: .long 0
 frameno: .long 0
diff --git a/src/video.c b/src/video.c
new file mode 100644
index 0000000..702273a
--- /dev/null
+++ b/src/video.c
@@ -0,0 +1,30 @@
+/*
+pcboot - bootable PC demo/game kernel
+Copyright (C) 2018  John Tsiombikas <nuclear@member.fsf.org>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY, without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+#include "video.h"
+#include <string.h>
+#include "int86.h"
+
+
+void set_vga_mode(int mode)
+{
+	struct int86regs regs;
+
+	memset(&regs, 0, sizeof regs);
+	regs.eax = mode;
+	int86(0x10, &regs);
+}
diff --git a/src/video.h b/src/video.h
new file mode 100644
index 0000000..645675a
--- /dev/null
+++ b/src/video.h
@@ -0,0 +1,9 @@
+#ifndef VIDEO_H_
+#define VIDEO_H_
+
+void set_vga_mode(int mode);
+
+/* defined in video_asm.s */
+void wait_vsync(void);
+
+#endif	/* VIDEO_H_ */
diff --git a/src/video_asm.s b/src/video_asm.s
new file mode 100644
index 0000000..1f7995c
--- /dev/null
+++ b/src/video_asm.s
@@ -0,0 +1,27 @@
+# pcboot - bootable PC demo/game kernel
+# Copyright (C) 2018  John Tsiombikas <nuclear@member.fsf.org>
+# 
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+# 
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY, without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+	.text
+
+	.global wait_vsync
+wait_vsync:
+	mov $0x3da, %dx
+0:	in %dx, %al
+	and $8, %al
+	jnz 0b
+0:	in %dx, %al
+	and $8, %al
+	jz 0b
+	ret
-- 
1.7.10.4