132 lines
3.4 KiB
ArmAsm
132 lines
3.4 KiB
ArmAsm
/* Real-mode interface: assembly-language portions.
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*
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* Initial version by Michael Brown <mbrown@fensystems.co.uk>, January 2004.
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*/
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#include "realmode.h"
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#include "callbacks.h"
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#if 1 /* CODE16 */
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#define BOCHSBP xchgw %bx,%bx
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#define NUM_PUSHA_REGS (8)
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#define NUM_SEG_REGS (6)
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.text
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.arch i386
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.section ".text16.nocompress", "ax", @progbits
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.code16
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.equ CR0_PE,1
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#ifdef GAS291
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#define DATA32 data32;
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#define ADDR32 addr32;
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#define LJMPI(x) ljmp x
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#else
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#define DATA32 data32
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#define ADDR32 addr32
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/* newer GAS295 require #define LJMPI(x) ljmp *x */
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#define LJMPI(x) ljmp x
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#endif
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#ifdef PXE_EXPORT
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/****************************************************************************
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* PXE CALLBACK INTERFACE
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*
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* Prepend this to rm_callback_interface to create a real-mode PXE
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* callback interface.
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****************************************************************************
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*/
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.section ".text16", "ax", @progbits
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.globl pxe_callback_interface
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.code16
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pxe_callback_interface:
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/* Macro to calculate offset of labels within code segment in
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* installed copy of code.
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*/
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#define INSTALLED(x) ( (x) - pxe_callback_interface )
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/****************************************************************************
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* PXE entry points (!PXE and PXENV+ APIs)
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****************************************************************************
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*/
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/* in_call mechanism for !PXE API calls */
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.globl _pxe_in_call_far
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_pxe_in_call_far:
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/* Prepend "PXE API call" and "API version 0x201" to stack */
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pushl $0x201
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jmp 1f
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/* in_call mechanism for PXENV+ API calls */
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.globl _pxenv_in_call_far
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_pxenv_in_call_far:
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/* Prepend "PXE API call" and "API version 0x200" to stack */
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pushl $0x200
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1: pushl $EB_OPCODE_PXE
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/* Perform real-mode in_call */
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call pxe_rm_in_call
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/* Return */
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addw $8, %sp
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lret
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/****************************************************************************
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* PXE installation check (INT 1A) code
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****************************************************************************
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*/
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.globl _pxe_intercept_int1a
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_pxe_intercept_int1a:
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pushfw
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cmpw $0x5650, %ax
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jne 2f
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1: /* INT 1A,5650 - Intercept */
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popfw
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/* Set up return values according to PXE spec: */
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movw $0x564e, %ax /* AX := 564Eh (VN) */
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pushw %cs:INSTALLED(_pxe_pxenv_segment)
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popw %es /* ES:BX := &(PXENV+ structure) */
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movw %cs:INSTALLED(_pxe_pxenv_offset), %bx
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clc /* CF is cleared */
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lret $2 /* 'iret' without reloading flags */
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2: /* INT 1A,other - Do not intercept */
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popfw
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ljmp %cs:*INSTALLED(_pxe_intercepted_int1a)
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.globl _pxe_intercepted_int1a
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_pxe_intercepted_int1a: .word 0,0
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.globl _pxe_pxenv_location
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_pxe_pxenv_location:
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_pxe_pxenv_offset: .word 0
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_pxe_pxenv_segment: .word 0
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pxe_rm_in_call:
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pxe_attach_rm:
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/* rm_callback_interface must be appended here */
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pxe_callback_interface_end:
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.globl _pxe_callback_interface_size
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.equ _pxe_callback_interface_size, pxe_callback_interface_end - pxe_callback_interface
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.globl pxe_callback_interface_size
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pxe_callback_interface_size:
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.word _pxe_callback_interface_size
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#else /* PXE_EXPORT */
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/* Define symbols used by the linker scripts, to prevent link errors */
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.globl _pxe_callback_interface_size
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.equ _pxe_callback_interface_size, 0
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#endif /* PXE_EXPORT */
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#else /* CODE16 */
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/* Define symbols used by the linker scripts, to prevent link errors */
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.globl _rm_callback_interface_size
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.equ _rm_callback_interface_size, 0
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.globl _pxe_callback_interface_size
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.equ _pxe_callback_interface_size, 0
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#endif /* CODE16 */
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