1 ;------------------------------------------------------------------------------ 2 ; 3 ; Copyright (c) 2006, Intel Corporation. All rights reserved.<BR> 4 ; This program and the accompanying materials 5 ; are licensed and made available under the terms and conditions of the BSD License 6 ; which accompanies this distribution. The full text of the license may be found at 7 ; http://opensource.org/licenses/bsd-license.php. 8 ; 9 ; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 10 ; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 11 ; 12 ; Module Name: 13 ; 14 ; ReadDr4.Asm 15 ; 16 ; Abstract: 17 ; 18 ; AsmReadDr4 function 19 ; 20 ; Notes: 21 ; 22 ;------------------------------------------------------------------------------ 23 24 SECTION .text 25 26 ;------------------------------------------------------------------------------ 27 ; UINTN 28 ; EFIAPI 29 ; AsmReadDr4 ( 30 ; VOID 31 ; ); 32 ;------------------------------------------------------------------------------ 33 global ASM_PFX(AsmReadDr4) 34 ASM_PFX(AsmReadDr4): 35 ; 36 ; DR4 is alias to DR6 only if DE (in CR4) is cleared. Otherwise, reading 37 ; this register will cause a #UD exception. 38 ; 39 ; MS assembler doesn't support this instruction since no one would use it 40 ; under normal circustances. Here opcode is used. 41 ; 42 DB 0xf, 0x21, 0xe0 43 ret 44 45
