From acb5161d7384e6b6352c0a9f3cc067621fbf28ad Mon Sep 17 00:00:00 2001 From: Alex AUVOLAT Date: Fri, 28 Mar 2014 17:16:09 +0100 Subject: Import and compile article 6.75 --- sos-code-article6.75/hwcore/cpu_context_switch.S | 128 +++++++++++++++++++++++ 1 file changed, 128 insertions(+) create mode 100644 sos-code-article6.75/hwcore/cpu_context_switch.S (limited to 'sos-code-article6.75/hwcore/cpu_context_switch.S') diff --git a/sos-code-article6.75/hwcore/cpu_context_switch.S b/sos-code-article6.75/hwcore/cpu_context_switch.S new file mode 100644 index 0000000..4499c91 --- /dev/null +++ b/sos-code-article6.75/hwcore/cpu_context_switch.S @@ -0,0 +1,128 @@ +/* Copyright (C) 2005 David Decotigny + Copyright (C) 2000-2004, The KOS team + + 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 2 + 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, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, + USA. +*/ +#define ASM_SOURCE 1 + + +.file "cpu_context_switch.S" + +.text + + +.globl sos_cpu_context_switch +.type sos_cpu_context_switch, @function +sos_cpu_context_switch: + // arg2= to_context -- esp+64 + // arg1= from_context -- esp+60 + // caller ip -- esp+56 + pushf // (eflags) esp+52 + pushl %cs // (cs) esp+48 + pushl $resume_pc // (ip) esp+44 + pushl $0 // (error code) esp+40 + pushl %ebp // esp+36 + pushl %edi // esp+32 + pushl %esi // esp+28 + pushl %edx // esp+24 + pushl %ecx // esp+20 + pushl %ebx // esp+16 + pushl %eax // esp+12 + subl $2, %esp // (alignment) esp+10 + pushw %ss // esp+8 + pushw %ds // esp+6 + pushw %es // esp+4 + pushw %fs // esp+2 + pushw %gs // esp + + /* + * Now that the original eax/ebx are stored, we can use them safely + */ + + /* Store the address of the saved context */ + movl 60(%esp), %ebx + movl %esp, (%ebx) + + /* This is the proper context switch ! We change the stack here */ + movl 64(%esp), %esp + + /* Restore the CPU context */ + popw %gs + popw %fs + popw %es + popw %ds + popw %ss + addl $2,%esp + popl %eax + popl %ebx + popl %ecx + popl %edx + popl %esi + popl %edi + popl %ebp + addl $4, %esp /* Ignore "error code" */ + + /* This restores the eflags, the cs and the eip registers */ + iret /* equivalent to: popfl ; ret */ + +resume_pc: + // Same context as that when sos_cpu_context_switch got called + // arg2= to_context -- esp+8 + // arg1= from_context -- esp+4 + // caller ip -- esp + ret + + + +/* ------------------------- */ +.globl sos_cpu_context_exit_to +.type sos_cpu_context_exit_to, @function +sos_cpu_context_exit_to: + // arg3= reclaiming_arg -- esp+12 + // arg2= reclaiming_func -- esp+8 + // arg1= to_context -- esp+4 + // caller ip -- esp + + /* Store the current SP in a temporary register */ + movl %esp, %eax + + /* This is the proper context switch ! We change the stack here */ + movl 4(%eax), %esp + + /* Call the reclaiming function (remember: the old frame address + is stored in eax) */ + pushl 12(%eax) + call *8(%eax) + addl $4, %esp + + /* Restore the CPU context */ + popw %gs + popw %fs + popw %es + popw %ds + popw %ss + addl $2,%esp + popl %eax + popl %ebx + popl %ecx + popl %edx + popl %esi + popl %edi + popl %ebp + addl $4, %esp /* Ignore "error code" */ + + /* This restores the eflags, the cs and the eip registers */ + iret /* equivalent to: popfl ; ret */ -- cgit v1.2.3