Assembly Code Snippet to measure base CPU Frequency

EUROASM AutoSegment=Yes, CPU=X64, SIMD=AVX2
getbase PROGRAM Format=PE, Width=64, Model=Flat, IconFile=, Entry=main:

INCLUDE winscon.htm, winabi.htm, cpuext64.htm

MsgFmt D "TSC Ticks per 1 s = %%d[u]; Base CPU Frequency is %%f[p2] GHz",13,10,0
Ticks DB Q
Freq DB Q
Divider DO Q 1_000_000_000
    
LINK cvirt.lib

main: nop
	WinABI SetStdioWindowOptions,0,0 ; prevent to move to front
    WinABI GetCurrentThread ; This one will be in RAX
    WinABI SetThreadAffinityMask, RAX, 1 ; RCX is thread param (core#)
    WinABI SetThreadPriority, RAX, 15 ; RCX is thread param (core#)
    WinABI QueryPerformanceFrequency, Freq
	mov r15, [Freq]

	WinABI QueryPerformanceCounter, Ticks
	mov r14, [Ticks] ; r10 - initial

	CPUID
    RDTSC
    SHL RDX, 32
    OR RAX, RDX
    MOV R13, RAX ; R13 will hold initial Time Stamp counter value
	
align 16
L1:
    RDTSCP
    SHL RDX, 32
    OR RAX, RDX
    SUB RAX, R13 ; Subtract previous stamp
	mov r12, rax ; R12 is the TSC difference

	WinABI QueryPerformanceCounter, Ticks
	mov r11, [Ticks] ; r10 - was initial
	sub r11, r14
	cmp r11, r15 ; Frequency, count one second
	jle L1

    movq xmm0, r12 ; R12 is now amount of TSC Ticks per second
    movq xmm1, [Divider]
    divsd xmm0, xmm1
    WinABI FmtOut, MsgFmt, r12, xmm0 ; Float Point

jmp main
	TerminateProgram

ENDPROGRAM