diff options
Diffstat (limited to 'sysdeps/standalone/i386/start.S')
| -rw-r--r-- | sysdeps/standalone/i386/start.S | 302 |
1 files changed, 150 insertions, 152 deletions
diff --git a/sysdeps/standalone/i386/start.S b/sysdeps/standalone/i386/start.S index 8331a331c1..41e0bfb135 100644 --- a/sysdeps/standalone/i386/start.S +++ b/sysdeps/standalone/i386/start.S @@ -1,23 +1,22 @@ -/* Copyright (C) 1994 Free Software Foundation, Inc. +/* Copyright (C) 1994, 1997 Free Software Foundation, Inc. Contributed by Joel Sherrill (jsherril@redstone-emh2.army.mil), On-Line Applications Research Corporation. - -This file is part of the GNU C Library. - -The GNU C Library is free software; you can redistribute it and/or -modify it under the terms of the GNU Library General Public License as -published by the Free Software Foundation; either version 2 of the -License, or (at your option) any later version. - -The GNU C Library 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 -Library General Public License for more details. - -You should have received a copy of the GNU Library General Public -License along with the GNU C Library; see the file COPYING.LIB. If -not, write to the Free Software Foundation, Inc., 675 Mass Ave, -Cambridge, MA 02139, USA. */ + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public License as + published by the Free Software Foundation; either version 2 of the + License, or (at your option) any later version. + + The GNU C Library 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 + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. If not, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ /* entry.s * @@ -28,28 +27,28 @@ Cambridge, MA 02139, USA. */ * */ - .data - .global _Do_Load_IDT - .global _Do_Load_GDT + .data + .global _Do_Load_IDT + .global _Do_Load_GDT - .text + .text .global start # GNU default entry point - .global _establish_stack + .global _establish_stack - .global _bsp_start - .global _load_segments - .global __exit + .global _bsp_start + .global _load_segments + .global __exit start: - nop - cli # DISABLE INTERRUPTS!!! + nop + cli # DISABLE INTERRUPTS!!! # # Load the segment registers # # NOTE: Upon return, gs will contain the segment descriptor for # a segment which maps directly to all of physical memory. # - jmp _load_segments # load board dependent segments + jmp _load_segments # load board dependent segments # # Set up the stack @@ -57,102 +56,102 @@ start: _establish_stack: - movl $stack_end,%esp # set stack pointer - movl $stack_end,%ebp # set base pointer + movl $stack_end,%esp # set stack pointer + movl $stack_end,%ebp # set base pointer # # Zero out the BSS segment # zero_bss: - cld # make direction flag count up - movl $_end,%ecx # find end of .bss - movl $_bss_start,%edi # edi = beginning of .bss - subl %edi,%ecx # ecx = size of .bss in bytes - shrl $2,%ecx # size of .bss in longs - xorl %eax,%eax # value to clear out memory - repne # while ecx != 0 - stosl # clear a long in the bss + cld # make direction flag count up + movl $_end,%ecx # find end of .bss + movl $_bss_start,%edi # edi = beginning of .bss + subl %edi,%ecx # ecx = size of .bss in bytes + shrl $2,%ecx # size of .bss in longs + xorl %eax,%eax # value to clear out memory + repne # while ecx != 0 + stosl # clear a long in the bss # # Set the C heap information for malloc # - movl $heap_size,___C_heap_size # set ___C_heap_size - movl $heap_memory,___C_heap_start # set ___C_heap_start + movl $heap_size,___C_heap_size # set ___C_heap_size + movl $heap_memory,___C_heap_start # set ___C_heap_start # # Copy the Global Descriptor Table to our space # - sgdt _Original_GDTR # save original GDT - movzwl _Original_GDTR_limit,%ecx # size of GDT in bytes; limit - # is 8192 entries * 8 bytes per + sgdt _Original_GDTR # save original GDT + movzwl _Original_GDTR_limit,%ecx # size of GDT in bytes; limit + # is 8192 entries * 8 bytes per - # make ds:esi point to the original GDT + # make ds:esi point to the original GDT - movl _Original_GDTR_base,%esi - push %ds # save ds - movw %gs,%ax - movw %ax,%ds + movl _Original_GDTR_base,%esi + push %ds # save ds + movw %gs,%ax + movw %ax,%ds - # make es:edi point to the new (our copy) GDT - movl $_Global_descriptor_table,%edi + # make es:edi point to the new (our copy) GDT + movl $_Global_descriptor_table,%edi - rep - movsb # copy the GDT (ds:esi -> es:edi) + rep + movsb # copy the GDT (ds:esi -> es:edi) - pop %ds # restore ds - - # Build and load new contents of GDTR - movw _Original_GDTR_limit,%ecx # set new limit - movw %cx,_New_GDTR_limit + pop %ds # restore ds - push $_Global_descriptor_table - push %es - call _Logical_to_physical - addl $6,%esp - movl %eax,_New_GDTR_base # set new base + # Build and load new contents of GDTR + movw _Original_GDTR_limit,%ecx # set new limit + movw %cx,_New_GDTR_limit - cmpb $0,_Do_Load_GDT # Should the new GDT be loaded? - je no_gdt_load # NO, then branch - lgdt _New_GDTR # load the new GDT + push $_Global_descriptor_table + push %es + call _Logical_to_physical + addl $6,%esp + movl %eax,_New_GDTR_base # set new base + + cmpb $0,_Do_Load_GDT # Should the new GDT be loaded? + je no_gdt_load # NO, then branch + lgdt _New_GDTR # load the new GDT no_gdt_load: # # Copy the Interrupt Descriptor Table to our space # - sidt _Original_IDTR # save original IDT - movzwl _Original_IDTR_limit,%ecx # size of IDT in bytes; limit - # is 256 entries * 8 bytes per - + sidt _Original_IDTR # save original IDT + movzwl _Original_IDTR_limit,%ecx # size of IDT in bytes; limit + # is 256 entries * 8 bytes per + - # make ds:esi point to the original IDT - movl _Original_IDTR_base,%esi + # make ds:esi point to the original IDT + movl _Original_IDTR_base,%esi - push %ds # save ds - movw %gs,%ax - movw %ax,%ds + push %ds # save ds + movw %gs,%ax + movw %ax,%ds - # make es:edi point to the new (our copy) IDT - movl $_Interrupt_descriptor_table,%edi + # make es:edi point to the new (our copy) IDT + movl $_Interrupt_descriptor_table,%edi - rep - movsb # copy the IDT (ds:esi -> es:edi) - pop %ds # restore ds + rep + movsb # copy the IDT (ds:esi -> es:edi) + pop %ds # restore ds - # Build and load new contents of IDTR - movw _Original_IDTR_limit,%ecx # set new limit - movw %cx,_New_IDTR_limit + # Build and load new contents of IDTR + movw _Original_IDTR_limit,%ecx # set new limit + movw %cx,_New_IDTR_limit - push $_Interrupt_descriptor_table - push %es - call _Logical_to_physical - addl $6,%esp - movl %eax,_New_IDTR_base # set new base + push $_Interrupt_descriptor_table + push %es + call _Logical_to_physical + addl $6,%esp + movl %eax,_New_IDTR_base # set new base - cmpb $0,_Do_Load_IDT # Should the new IDT be loaded? - je no_idt_load # NO, then branch - lidt _New_IDTR # load the new IDT + cmpb $0,_Do_Load_IDT # Should the new IDT be loaded? + je no_idt_load # NO, then branch + lidt _New_IDTR # load the new IDT no_idt_load: # @@ -163,44 +162,44 @@ no_idt_load: # exception. # - fninit # MUST USE NO-WAIT FORM + fninit # MUST USE NO-WAIT FORM - call __Board_Initialize # initialize the board + call __Board_Initialize # initialize the board - pushl $0 # envp = NULL - pushl $0 # argv = NULL - pushl $0 # argc = NULL - call ___libc_init # initialize the library and - # call main - addl $12,%esp - - pushl $0 # argc = NULL - call __exit # call the Board specific exit - addl $4,%esp + pushl $0 # envp = NULL + pushl $0 # argv = NULL + pushl $0 # argc = NULL + call ___libc_init # initialize the library and + # call main + addl $12,%esp + + pushl $0 # argc = NULL + call __exit # call the Board specific exit + addl $4,%esp # # Clean up # - .global _Bsp_cleanup + .global _Bsp_cleanup - .global _return_to_monitor + .global _return_to_monitor _Bsp_cleanup: - cmpb $0,_Do_Load_IDT # Was the new IDT loaded? - je no_idt_restore # NO, then branch - lidt _Original_IDTR # restore the new IDT + cmpb $0,_Do_Load_IDT # Was the new IDT loaded? + je no_idt_restore # NO, then branch + lidt _Original_IDTR # restore the new IDT no_idt_restore: - cmpb $0,_Do_Load_GDT # Was the new GDT loaded? - je no_gdt_restore # NO, then branch - lgdt _Original_GDTR # restore the new GDT + cmpb $0,_Do_Load_GDT # Was the new GDT loaded? + je no_gdt_restore # NO, then branch + lgdt _Original_GDTR # restore the new GDT no_gdt_restore: - jmp _return_to_monitor + jmp _return_to_monitor # -# void *Logical_to_physical( +# void *Logical_to_physical( # rtems_unsigned16 segment, # void *address # ); @@ -208,28 +207,28 @@ no_gdt_restore: # Returns thirty-two bit physical address for segment:address. # - .global _Logical_to_physical + .global _Logical_to_physical .set SEGMENT_ARG, 4 .set ADDRESS_ARG, 8 _Logical_to_physical: - xorl %eax,%eax # clear eax - movzwl SEGMENT_ARG(%esp),%ecx # ecx = segment value - movl $_Global_descriptor_table,%edx # edx = address of our GDT - addl %ecx,%edx # edx = address of desired entry - movb 7(%edx),%ah # ah = base 31:24 - movb 4(%edx),%al # al = base 23:16 - shll $16,%eax # move ax into correct bits - movw 2(%edx),%ax # ax = base 0:15 - movl ADDRESS_ARG(%esp),%ecx # ecx = address to convert - addl %eax,%ecx # ecx = physical address equivalent - movl %ecx,%eax # eax = ecx - ret - + xorl %eax,%eax # clear eax + movzwl SEGMENT_ARG(%esp),%ecx # ecx = segment value + movl $_Global_descriptor_table,%edx # edx = address of our GDT + addl %ecx,%edx # edx = address of desired entry + movb 7(%edx),%ah # ah = base 31:24 + movb 4(%edx),%al # al = base 23:16 + shll $16,%eax # move ax into correct bits + movw 2(%edx),%ax # ax = base 0:15 + movl ADDRESS_ARG(%esp),%ecx # ecx = address to convert + addl %eax,%ecx # ecx = physical address equivalent + movl %ecx,%eax # eax = ecx + ret + # -# void *Physical_to_logical( +# void *Physical_to_logical( # rtems_unsigned16 segment, # void *address # ); @@ -237,41 +236,41 @@ _Logical_to_physical: # Returns thirty-two bit physical address for segment:address. # - .global _Physical_to_logical + .global _Physical_to_logical #.set SEGMENT_ARG, 4 #.set ADDRESS_ARG, 8 -- use sets from above _Physical_to_logical: - xorl %eax,%eax # clear eax - movzwl SEGMENT_ARG(%esp),%ecx # ecx = segment value - movl $_Global_descriptor_table,%edx # edx = address of our GDT - addl %ecx,%edx # edx = address of desired entry - movb 7(%edx),%ah # ah = base 31:24 - movb 4(%edx),%al # al = base 23:16 - shll $16,%eax # move ax into correct bits - movw 2(%edx),%ax # ax = base 0:15 - movl ADDRESS_ARG(%esp),%ecx # ecx = address to convert - subl %eax,%ecx # ecx = logical address equivalent - movl %ecx,%eax # eax = ecx - ret - + xorl %eax,%eax # clear eax + movzwl SEGMENT_ARG(%esp),%ecx # ecx = segment value + movl $_Global_descriptor_table,%edx # edx = address of our GDT + addl %ecx,%edx # edx = address of desired entry + movb 7(%edx),%ah # ah = base 31:24 + movb 4(%edx),%al # al = base 23:16 + shll $16,%eax # move ax into correct bits + movw 2(%edx),%ax # ax = base 0:15 + movl ADDRESS_ARG(%esp),%ecx # ecx = address to convert + subl %eax,%ecx # ecx = logical address equivalent + movl %ecx,%eax # eax = ecx + ret + /* * Data Declarations. Start with a macro which helps declare space. */ - .bss + .bss #define DECLARE_SPACE(_name,_space,_align) \ - .globl _name ; \ - .align _align ; \ + .globl _name ; \ + .align _align ; \ _name##: .space _space #define DECLARE_LABEL(_name) \ - .globl _name ; \ -_name##: + .globl _name ; \ +_name##: #define DECLARE_PTR(_name) DECLARE_SPACE(_name,4,2) #define DECLARE_U32(_name) DECLARE_SPACE(_name,4,2) @@ -287,7 +286,7 @@ DECLARE_PTR(environ) DECLARE_LABEL(_errno) DECLARE_U32(errno) -/* +/* * Miscellaneous Variables used to restore the CPU state. * * Start with a macro to declare the space for the contents of @@ -295,8 +294,8 @@ DECLARE_U32(errno) */ #define DECLARE_DTR_SPACE(_name) \ - .global _name ; \ - .align 4 ; \ + .global _name ; \ + .align 4 ; \ _name##: ; \ _name##_limit: .space 2 ; \ _name##_base: .space 4 @@ -316,8 +315,7 @@ DECLARE_SPACE(_Physical_base_of_cs,4,4) * Stack Size and Space */ - .set stack_size, 0x20000 + .set stack_size, 0x20000 DECLARE_SPACE(stack_memory,stack_size,4) DECLARE_LABEL(stack_end) - |