emudbg/asm_function.asm at master · mojtabafalleh/emudbg · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
.code

PUBLIC rdtsc_asm
PUBLIC xgetbv_asm
PUBLIC fnstcw_asm
PUBLIC read_mxcsr_asm
; uint64_t xgetbv_asm(uint32_t ecx)

fnstcw_asm PROC
    fnstcw [rcx]
    ret
fnstcw_asm ENDP

read_mxcsr_asm PROC
    stmxcsr [rcx]
    ret
read_mxcsr_asm ENDP

xgetbv_asm PROC
    ; ecx is in ecx already
    xgetbv              ; output edx:eax
    shl rdx, 32         ; shift edx to high 32 bits
    or rax, rdx         ; combine edx:eax to rax
    ret

xgetbv_asm ENDP

PUBLIC rdtsc_asm
; uint64_t rdtsc_asm()

rdtsc_asm PROC
    rdtsc
    shl rdx, 32
    or rax, rdx
    ret
rdtsc_asm ENDP

ReadGDTR PROC
    sgdt fword ptr [rcx]   ; GDTR -> [RCX]
    ret
ReadGDTR ENDP

END