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-rw-r--r--com32/mboot/apm.c87
1 files changed, 87 insertions, 0 deletions
diff --git a/com32/mboot/apm.c b/com32/mboot/apm.c
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+/* ----------------------------------------------------------------------- *
+ *
+ * Copyright 2009 Intel Corporation; author: H. Peter Anvin
+ *
+ * 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, Inc., 51 Franklin St, Fifth Floor,
+ * Boston MA 02110-1301, USA; either version 2 of the License, or
+ * (at your option) any later version; incorporated herein by reference.
+ *
+ * Based on code from the Linux kernel:
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ * Copyright 2007 rPath, Inc. - All Rights Reserved
+ *
+ * Original APM BIOS checking by Stephen Rothwell, May 1994
+ * (sfr@canb.auug.org.au)
+ *
+ * This file is part of the Linux kernel, and is made available under
+ * the terms of the GNU General Public License version 2.
+ *
+ * ----------------------------------------------------------------------- */
+
+
+/*
+ * apm.c
+ *
+ * APM information for Multiboot
+ */
+
+#include "mboot.h"
+#include <com32.h>
+
+void mboot_apm(void)
+{
+ static struct apm_info apm;
+ com32sys_t ireg, oreg;
+
+ memset(&ireg, 0, sizeof ireg);
+
+ ireg.eax.w[0] = 0x5300;
+ __intcall(0x15, &ireg, &oreg);
+
+ if (oreg.eflags.l & EFLAGS_CF)
+ return; /* No APM BIOS */
+
+ if (oreg.ebx.w[0] != 0x504d)
+ return; /* No "PM" signature */
+
+ if (!(oreg.ecx.w[0] & 0x02))
+ return; /* 32 bits not supported */
+
+ /* Disconnect first, just in case */
+ ireg.eax.b[0] = 0x04;
+ __intcall(0x15, &ireg, &oreg);
+
+ /* 32-bit connect */
+ ireg.eax.b[0] = 0x03;
+ __intcall(0x15, &ireg, &oreg);
+
+ apm.cseg = oreg.eax.w[0];
+ apm.offset = oreg.ebx.l;
+ apm.cseg_16 = oreg.ecx.w[0];
+ apm.dseg_16 = oreg.edx.w[0];
+ apm.cseg_len = oreg.esi.w[0];
+ apm.cseg_16_len = oreg.esi.w[1];
+ apm.dseg_16_len = oreg.edi.w[0];
+
+ /* Redo the installation check as the 32-bit connect;
+ some BIOSes return different flags this way... */
+
+ ireg.eax.b[0] = 0x00;
+ __intcall(0x15, &ireg, &oreg);
+
+ if ((oreg.eflags.l & EFLAGS_CF) || (oreg.ebx.w[0] != 0x504d)) {
+ /* Failure with 32-bit connect, try to disconect and ignore */
+ ireg.eax.b[0] = 0x04;
+ __intcall(0x15, &ireg, NULL);
+ return;
+ }
+
+ apm.version = oreg.eax.w[0];
+
+ mbinfo.apm_table = map_data(&apm, sizeof apm, 4, false);
+ if (mbinfo.apm_table)
+ mbinfo.flags |= MB_INFO_APM_TABLE;
+}