OSCL-LXR |
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0001 /* SPDX-License-Identifier: GPL-2.0-or-later */ 0002 /* ----------------------------------------------------------------------- 0003 * 0004 * Copyright 2009-2014 Intel Corporation; author H. Peter Anvin 0005 * 0006 * ----------------------------------------------------------------------- */ 0007 0008 /* 0009 * "Glove box" for BIOS calls. Avoids the constant problems with BIOSes 0010 * touching registers they shouldn't be. 0011 */ 0012 0013 .code16 0014 .section ".inittext","ax" 0015 .globl intcall 0016 .type intcall, @function 0017 intcall: 0018 /* Self-modify the INT instruction. Ugly, but works. */ 0019 cmpb %al, 3f 0020 je 1f 0021 movb %al, 3f 0022 jmp 1f /* Synchronize pipeline */ 0023 1: 0024 /* Save state */ 0025 pushfl 0026 pushw %fs 0027 pushw %gs 0028 pushal 0029 0030 /* Copy input state to stack frame */ 0031 subw $44, %sp 0032 movw %dx, %si 0033 movw %sp, %di 0034 movw $11, %cx 0035 rep; movsd 0036 0037 /* Pop full state from the stack */ 0038 popal 0039 popw %gs 0040 popw %fs 0041 popw %es 0042 popw %ds 0043 popfl 0044 0045 /* Actual INT */ 0046 .byte 0xcd /* INT opcode */ 0047 3: .byte 0 0048 0049 /* Push full state to the stack */ 0050 pushfl 0051 pushw %ds 0052 pushw %es 0053 pushw %fs 0054 pushw %gs 0055 pushal 0056 0057 /* Re-establish C environment invariants */ 0058 cld 0059 movzwl %sp, %esp 0060 movw %cs, %ax 0061 movw %ax, %ds 0062 movw %ax, %es 0063 0064 /* Copy output state from stack frame */ 0065 movw 68(%esp), %di /* Original %cx == 3rd argument */ 0066 andw %di, %di 0067 jz 4f 0068 movw %sp, %si 0069 movw $11, %cx 0070 rep; movsd 0071 4: addw $44, %sp 0072 0073 /* Restore state and return */ 0074 popal 0075 popw %gs 0076 popw %fs 0077 popfl 0078 retl 0079 .size intcall, .-intcall
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