UASM64-Library/CPU_RDSEED_Supported.asm at main · mrfearless/UASM64-Library · GitHub

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;==============================================================================
;
; UASM64 Library
;
; https://github.com/mrfearless/UASM64-Library
;
;==============================================================================
.686
.MMX
.XMM
.x64

option casemap : none
IF @Platform EQ 1
option win64 : 11
ENDIF
option frame : auto

include UASM64.inc

.CODE

UASM64_ALIGN
;------------------------------------------------------------------------------
; CPU_RDSEED_Supported
;
; Check if the RDSEED instruction is supported.
;
; Parameters:
;
; There are no parameters.
;
; Returns:
;
; TRUE if RDSEED instruction is supported, or FALSE otherwise.
;
; Notes:
;
; https://en.wikipedia.org/wiki/RDRAND
;
; See Also:
;
; CPU_CPUID_Supported, CPU_RDSEED_Supported
;
;------------------------------------------------------------------------------
CPU_RDSEED_Supported PROC FRAME USES RBX RCX RDX

    Invoke CPU_CPUID_Supported
    .IF rax == FALSE
        jmp CPU_RDSEED_Supported_Error
    .ENDIF

    xor rax, rax
    xor rbx, rbx
    xor rcx, rcx
    xor rdx, rdx

    mov eax, 7
    cpuid
    shr ebx, 18
    and ebx, 1
    mov eax, ebx

    jmp CPU_RDSEED_Supported_Exit

CPU_RDSEED_Supported_Error:

    mov rax, 0

CPU_RDSEED_Supported_Exit:

    ret
CPU_RDSEED_Supported ENDP


END