Initial source

1 files changed, 77 insertions, 0 deletions

diff --git a/i386/i386at/immc.c b/i386/i386at/immc.c
new file mode 100644
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+++ b/i386/i386at/immc.c
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+/* 
+ * Copyright (c) 1995-1994 The University of Utah and
+ * the Computer Systems Laboratory at the University of Utah (CSL).
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify and distribute this software is hereby
+ * granted provided that (1) source code retains these copyright, permission,
+ * and disclaimer notices, and (2) redistributions including binaries
+ * reproduce the notices in supporting documentation, and (3) all advertising
+ * materials mentioning features or use of this software display the following
+ * acknowledgement: ``This product includes software developed by the
+ * Computer Systems Laboratory at the University of Utah.''
+ *
+ * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
+ * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
+ * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * CSL requests users of this software to return to csl-dist@cs.utah.edu any
+ * improvements that they make and grant CSL redistribution rights.
+ *
+ *      Author: Bryan Ford, University of Utah CSL
+ */
+
+#ifdef ENABLE_IMMEDIATE_CONSOLE
+
+/* This is a special "feature" (read: kludge)
+   intended for use only for kernel debugging.
+   It enables an extremely simple console output mechanism
+   that sends text straight to CGA/EGA/VGA video memory.
+   It has the nice property of being functional right from the start,
+   so it can be used to debug things that happen very early
+   before any devices are initialized.  */
+
+int immediate_console_enable = 1;
+
+void
+immc_cnputc(unsigned char c)
+{
+	static int ofs = -1;
+
+	if (!immediate_console_enable)
+		return;
+	if (ofs < 0)
+	{
+		ofs = 0;
+		immc_cnputc('\n');
+	}
+	else if (c == '\n')
+	{
+		bcopy(0xb8000+80*2, 0xb8000, 80*2*24);
+		bzero(0xb8000+80*2*24, 80*2);
+		ofs = 0;
+	}
+	else
+	{
+		volatile unsigned char *p;
+
+		if (ofs >= 80)
+		{
+			immc_cnputc('\r');
+			immc_cnputc('\n');
+		}
+
+		p = (void*)0xb8000 + 80*2*24 + ofs*2;
+		p[0] = c;
+		p[1] = 0x0f;
+		ofs++;
+	}
+}
+
+int immc_cnmaygetc(void)
+{
+	return -1;
+}
+
+#endif ENABLE_IMMEDIATE_CONSOLE
+