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-rw-r--r--src/arch/x86/thread_switch.S58
1 files changed, 58 insertions, 0 deletions
diff --git a/src/arch/x86/thread_switch.S b/src/arch/x86/thread_switch.S
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+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2013 Google, Inc.
+ *
+ * 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; version 2 of the License.
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc.
+ */
+.code32
+.text
+
+/*
+ * stack layout after pushad:
+ * +------------+
+ * | save stack | <-- esp + 0x28
+ * +------------+
+ * | new stack | <-- esp + 0x24
+ * +------------+
+ * | ret addr | <-- esp + 0x20
+ * +------------+
+ * | eax | <-- esp + 0x1c
+ * +------------+
+ * | ecx | <-- esp + 0x18
+ * +------------+
+ * | edx | <-- esp + 0x14
+ * +------------+
+ * | ebx | <-- esp + 0x10
+ * +------------+
+ * | orig esp | <-- esp + 0x0c
+ * +------------+
+ * | ebp | <-- esp + 0x08
+ * +------------+
+ * | esi | <-- esp + 0x04
+ * +------------+
+ * | edi | <-- esp + 0x00
+ * +------------+
+ */
+.globl switch_to_thread
+switch_to_thread:
+ pusha
+ /* Save the current stack */
+ movl 0x28(%esp), %ebx
+ movl %esp, (%ebx)
+ /* Switch to the new stack. */
+ movl 0x24(%esp), %eax
+ movl %eax, %esp
+ popa
+ ret
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