timesupA.mac@ 53401

Last change on this file since 53401 was 44528, checked in by vboxsync, 12 years ago
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1	; $Id: timesupA.mac 44528 2013-02-04 14:27:54Z vboxsync $
2	;; @file
3	; IPRT - Time using SUPLib, the Assembly Code Template.
4	;
5
6	;
7	; Copyright (C) 2006-2011 Oracle Corporation
8	;
9	; This file is part of VirtualBox Open Source Edition (OSE), as
10	; available from http://www.virtualbox.org. This file is free software;
11	; you can redistribute it and/or modify it under the terms of the GNU
12	; General Public License (GPL) as published by the Free Software
13	; Foundation, in version 2 as it comes in the "COPYING" file of the
14	; VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15	; hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16	;
17	; The contents of this file may alternatively be used under the terms
18	; of the Common Development and Distribution License Version 1.0
19	; (CDDL) only, as it comes in the "COPYING.CDDL" file of the
20	; VirtualBox OSE distribution, in which case the provisions of the
21	; CDDL are applicable instead of those of the GPL.
22	;
23	; You may elect to license modified versions of this file under the
24	; terms and conditions of either the GPL or the CDDL or both.
25	;
26
27	%ifdef RT_ARCH_X86
28	;;
29	; The x86 assembly implementation of the assembly routines.
30	;
31	; @returns Nanosecond timestamp.
32	; @param pData Pointer to the nanosecond timestamp data.
33	;
34	BEGINPROC rtTimeNanoTSInternalAsm
35	;
36	; Variable definitions.
37	;
38	%define pData [ebp + 08h]
39	%define u64RetNanoTS_Hi [ebp - 04h]
40	%define u64RetNanoTS [ebp - 08h]
41	%define u32UpdateIntervalNS [ebp - 0ch]
42	%define u32UpdateIntervalTSC [ebp - 10h]
43	%define u64TSC_Hi [ebp - 14h]
44	%define u64TSC [ebp - 18h]
45	%define u64CurNanoTS_Hi [ebp - 1ch]
46	%define u64CurNanoTS [ebp - 20h]
47	%define u64PrevNanoTS_Hi [ebp - 24h]
48	%define u64PrevNanoTS [ebp - 28h]
49	%define u32TransactionId [ebp - 2ch]
50	%define u32ApicIdPlus [ebp - 30h]
51	%define TmpVar [ebp - 34h]
52	%define SavedEBX [ebp - 38h]
53	%define SavedEDI [ebp - 3ch]
54	%define SavedESI [ebp - 40h]
55
56	;
57	; Prolog.
58	;
59	push ebp
60	mov ebp, esp
61	sub esp, 40h
62	mov SavedEBX, ebx
63	mov SavedEDI, edi
64	mov SavedESI, esi
65
66
67	;;
68	;; Read the GIP data and the previous value.
69	;;
70	.ReadGip:
71
72
73	;
74	; Load pGip and calc pGipCPU, setting u32ApicIdPlus if necessary.
75	;
76	%ifdef IMPORTED_SUPLIB
77	%ifdef IN_RING0
78	mov esi, IMP(g_SUPGlobalInfoPage)
79	%else
80	mov esi, IMP(g_pSUPGlobalInfoPage)
81	mov esi, [esi]
82	%endif
83	%else
84	mov esi, [NAME(g_pSUPGlobalInfoPage)]
85	%endif
86	or esi, esi
87	jz .Rediscover
88	cmp dword [esi + SUPGLOBALINFOPAGE.u32Magic], SUPGLOBALINFOPAGE_MAGIC
89	jne .Rediscover
90	%ifdef ASYNC_GIP
91	; u8ApicId = ASMGetApicId();
92	mov eax, 1
93	cpuid ; expensive
94	%ifdef NEED_TRANSACTION_ID
95	mov u32ApicIdPlus, ebx
96	%endif
97	; pGipCpu = &pGip->aCPU[pGip->aiCpuFromApicId[u8ApicId]];
98	shr ebx, 24
99	movzx ebx, word [esi + ebx * 2 + SUPGLOBALINFOPAGE.aiCpuFromApicId]
100	mov eax, SUPGIPCPU_size
101	mul ebx
102	lea edi, [esi + eax + SUPGLOBALINFOPAGE.aCPUs] ; edi == &pGip->aCPU[u8ApicId];
103	%else
104	lea edi, [esi + SUPGLOBALINFOPAGE.aCPUs] ; edi == &pGip->aCPU[0];
105	%endif
106
107	%ifdef NEED_TRANSACTION_ID
108	;
109	; Serialized loading of u32TransactionId.
110	;
111	mov ebx, [edi + SUPGIPCPU.u32TransactionId]
112	mov u32TransactionId, ebx
113	%ifdef USE_LFENCE
114	lfence
115	%else
116	lock xor dword TmpVar, 0
117	%endif
118	%endif
119
120	;
121	; Load the data and TSC.
122	;
123	mov eax, [esi + SUPGLOBALINFOPAGE.u32UpdateIntervalNS]
124	mov u32UpdateIntervalNS, eax ; esi is now free
125	mov edx, [edi + SUPGIPCPU.u32UpdateIntervalTSC]
126	mov u32UpdateIntervalTSC, edx
127	rdtsc
128	mov ecx, [edi + SUPGIPCPU.u64NanoTS]
129	mov u64CurNanoTS, ecx
130	mov esi, [edi + SUPGIPCPU.u64NanoTS + 4]
131	mov u64CurNanoTS_Hi, esi
132	mov ebx, [edi + SUPGIPCPU.u64TSC]
133	mov u64TSC, ebx
134	mov ecx, [edi + SUPGIPCPU.u64TSC + 4]
135	mov u64TSC_Hi, ecx
136
137	; u64PrevNanoTS = ASMAtomicReadU64(pu64Prev);
138	; This serializes load/save. And with the dependency on the
139	; RDTSC result, we try to make sure it has completed as well.
140	mov esi, pData
141	mov esi, [esi + RTTIMENANOTSDATA.pu64Prev]
142	mov ebx, eax
143	mov ecx, edx
144	lock cmpxchg8b [esi]
145	mov u64PrevNanoTS, eax
146	mov u64PrevNanoTS_Hi, edx
147
148	%undef SAVED_u64RetNanoTS
149	%ifdef NEED_TRANSACTION_ID
150	;
151	; Check that the GIP and CPU didn't change.
152	; We've already serialized all the loads and stores at this point.
153	;
154	%ifdef ASYNC_GIP
155	mov u64RetNanoTS, ebx
156	mov u64RetNanoTS_Hi, ecx
157	%define SAVED_u64RetNanoTS
158	mov eax, 1
159	cpuid
160	cmp u32ApicIdPlus, ebx
161	jne .ReadGip
162	%endif
163	mov esi, [edi + SUPGIPCPU.u32TransactionId]
164	cmp esi, u32TransactionId
165	jne .ReadGip
166	test esi, 1
167	jnz .ReadGip
168	%endif ; NEED_TRANSACTION_ID
169	%ifdef SAVED_u64RetNanoTS
170	mov ebx, u64RetNanoTS
171	mov ecx, u64RetNanoTS_Hi
172	%endif
173
174	;;
175	;; Calc the timestamp.
176	;;
177	; u64RetNanoTS -= u64TSC;
178	sub ebx, u64TSC
179	sbb ecx, u64TSC_Hi
180
181	; if (u64RetNanoTS > u32UpdateIntervalTSC) -> jump
182	or ecx, ecx
183	jnz .OverFlow
184	cmp ebx, u32UpdateIntervalTSC
185	ja .OverFlow
186	mov eax, ebx
187	.ContinueCalcs: ; eax <= u32UpdateIntervalTSC
188	mul dword u32UpdateIntervalNS
189	div dword u32UpdateIntervalTSC
190	xor edx, edx
191
192	; u64RetNanoTS += u64CurNanoTS;
193	add eax, u64CurNanoTS
194	adc edx, u64CurNanoTS_Hi
195
196	;;
197	;; Compare it with the previous one.
198	;;
199	; if (RT_LIKELY( u64RetNanoTS > u64PrevNanoTS
200	; && u64RetNanoTS < u64PrevNanoTS + UINT64_C(86000000000000) /* 24h */))
201	;; @todo optimize this compare (/me too tired).
202	mov ecx, u64PrevNanoTS_Hi
203	mov ebx, u64PrevNanoTS
204	cmp edx, ecx
205	ja .Compare2
206	jb .DeltaPrevTooBig
207	cmp eax, ebx
208	jbe .DeltaPrevTooBig
209
210	.Compare2:
211	add ebx, 0x6F736000
212	adc ecx, 0x00004E37
213	cmp edx, ecx
214	jb .CompareDone
215	ja .DeltaPrevTooBig
216	cmp eax, ebx
217	jae .DeltaPrevTooBig
218	.CompareDone:
219
220
221	;;
222	;; Update the previous value with the u64RetNanoTS value.
223	;;
224	.Update:
225	; if (RT_LIKELY(ASMAtomicCmpXchgU64(&pData->u64Prev, u64RetNanoTS, u64PrevNanoTS)))
226	mov ebx, eax
227	mov ecx, edx
228	mov esi, pData
229	mov esi, [esi + RTTIMENANOTSDATA.pu64Prev]
230	mov eax, u64PrevNanoTS
231	mov edx, u64PrevNanoTS_Hi
232	lock cmpxchg8b [esi]
233	jnz .UpdateFailed
234
235	.Updated:
236	mov eax, ebx
237	mov edx, ecx
238
239	.Done:
240	mov esi, SavedESI
241	mov edi, SavedEDI
242	mov ebx, SavedEBX
243	leave
244	ret
245
246
247	;;
248	;; We've expired the interval, cap it. If we're here for the 2nd
249	;; time without any GIP update in-between, the checks against
250	;; pData->u64Prev below will force 1ns stepping.
251	;;
252	.OverFlow:
253	; u64Delta = u32UpdateIntervalTSC;
254	mov esi, pData
255	inc dword [esi + RTTIMENANOTSDATA.cExpired]
256	mov eax, u32UpdateIntervalTSC
257	jmp .ContinueCalcs
258
259
260	;;
261	;; u64DeltaPrev >= 24h
262	;;
263	;; eax:edx = u64RetNanoTS (to be adjusted)
264	;;
265	.DeltaPrevTooBig:
266	; uint64_t u64DeltaPrev = u64RetNanoTS - u64PrevNanoTS;
267	mov ebx, eax
268	sub ebx, u64PrevNanoTS
269	mov ecx, edx
270	sbb ecx, u64PrevNanoTS_Hi ; ebx:ecx = u64DeltaPrev
271
272	; else if ( (int64_t)u64DeltaPrev <= 0
273	; && (int64_t)u64DeltaPrev + u32UpdateIntervalNS * 2 >= 0)
274	; {
275	; /* Occasional - u64RetNanoTS is in the recent 'past' relative the previous call. */
276	; pData->c1nsSteps++;
277	; u64RetNanoTS = u64PrevNanoTS + 1;
278	; }
279	mov esi, u32UpdateIntervalNS
280	cmp ecx, 0
281	jl .PrevNotZero2ndTest
282	jg .DeltaPrevNotInRecentPast
283	cmp ebx, 0
284	ja .DeltaPrevNotInRecentPast
285
286	.PrevNotZero2ndTest:
287	add esi, esi ; ASSUMES: u32UpdateIntervalNS * 2 <= 32-bit.
288	xor edi, edi
289	add esi, ebx
290	adc edi, ecx
291	test edi, edi
292	js .DeltaPrevNotInRecentPast
293
294	.DeltaPrevInRecentPast:
295	mov esi, pData
296	inc dword [esi + RTTIMENANOTSDATA.c1nsSteps]
297	mov eax, u64PrevNanoTS
298	mov edx, u64PrevNanoTS_Hi
299	add eax, 1
300	adc edx, 0
301	jmp .Update
302
303	.DeltaPrevNotInRecentPast:
304	; else if (!u64PrevNanoTS) /* We're resuming (see TMVirtualResume). */
305	; /* do nothing */;
306	cmp dword u64PrevNanoTS, 0
307	jne .DeltaPrevNotZero
308	cmp dword u64PrevNanoTS_Hi, 0
309	jne .DeltaPrevNotZero
310	jmp .Update
311
312	.DeltaPrevNotZero:
313	; else
314	; {
315	; /* Something has gone bust, if negative offset it's real bad. */
316	; rtTimeNanoTSInternalBitch(pVM,
317	; }
318
319	; call C function that does the bitching.
320	mov u64RetNanoTS, eax
321	mov u64RetNanoTS_Hi, edx
322
323	mov edi, u64PrevNanoTS_Hi
324	mov esi, u64PrevNanoTS
325	push edi
326	push esi ; 4 - u64PrevNanoTS
327	push ecx
328	push ebx ; 3 - u64DeltaPrev
329	push edx
330	push eax ; 2 - u64RetNanoTS
331	mov eax, pData
332	push eax ; 1 - pData
333	call dword [eax + RTTIMENANOTSDATA.pfnBad]
334	add esp, 4*7
335
336	mov eax, u64RetNanoTS
337	mov edx, u64RetNanoTS_Hi
338	jmp .Update
339
340
341	;;
342	;; Attempt updating the previous value, provided we're still ahead of it.
343	;;
344	;; There is no point in recalculating u64NanoTS because we got preempted or if
345	;; we raced somebody while the GIP was updated, since these are events
346	;; that might occur at any point in the return path as well.
347	;;
348	;; eax:edx = *pData->u64Prev
349	;; ebx:ecx = u64RetNanoTS
350	;;
351	ALIGNCODE(16)
352	.UpdateFailed:
353	mov edi, pData
354	lock inc dword [edi + RTTIMENANOTSDATA.cUpdateRaces]
355	; for (i = 0; i < 10; i++)
356	mov edi, 10
357	.UpdateLoop:
358	; if (u64PrevNanoTS >= u64NanoTS)
359	; break;
360	cmp edx, ecx
361	jg .Updated
362	jne .UpdateLoopLess
363	cmp eax, ebx
364	jae .Updated
365	.UpdateLoopLess:
366	; retry
367	lock cmpxchg8b [esi]
368	jz .Updated
369	dec edi
370	jnz .UpdateLoop
371	jmp .Updated
372
373
374	;;
375	;; The GIP is seemingly invalid, redo the discovery.
376	;;
377	.Rediscover:
378	mov eax, pData
379	push eax
380	call [eax + RTTIMENANOTSDATA.pfnRediscover]
381	add esp, 4h
382	jmp .Done
383
384	;
385	; Cleanup variables
386	;
387	%undef pData
388	%undef u64Delta_Hi
389	%undef u64Delta
390	%undef u32UpdateIntervalNS
391	%undef u32UpdateIntervalTSC
392	%undef u64TSC_Hi
393	%undef u64TSC
394	%undef u64NanoTS_Hi
395	%undef u64NanoTS
396	%undef u64PrevNanoTS_Hi
397	%undef u64PrevNanoTS
398	%undef u32TransactionId
399	%undef u8ApicId
400
401	%else ; AMD64
402
403	;;
404	; The AMD64 assembly implementation of the assembly routines.
405	;
406	; @returns Nanosecond timestamp.
407	; @param pData gcc:rdi msc:rcx Pointer to the nanosecond timestamp data.
408	;
409	BEGINPROC rtTimeNanoTSInternalAsm
410	;
411	; Define variables and stack frame.
412	;
413	%define SavedRBX [rbp - 08h]
414	%define SavedR12 [rbp - 10h]
415	%define SavedR13 [rbp - 18h]
416	%define SavedRDI [rbp - 20h]
417	%define SavedRSI [rbp - 28h]
418	%define TmpVar [rbp - 30h]
419	%define TmpVar2 [rbp - 38h]
420	%ifdef NEED_TRANSACTION_ID
421	%ifdef ASYNC_GIP
422	%define SavedR14 [rbp - 40h]
423	%define SavedR15 [rbp - 48h]
424	%endif
425	%endif
426
427	%define pData rdi
428
429	%define u64TSC rsi
430	%define pGip rsi
431	%define pGipCPU r8
432	%define u32TransactionId r9d
433	%define u64CurNanoTS r10
434	%define u64PrevNanoTS r11 ; not parameter register
435	%define u32UpdateIntervalTSC r12d
436	%define u32UpdateIntervalTSC_64 r12
437	%define u32UpdateIntervalNS r13d
438	%define u32UpdateIntervalNS_64 r13
439	%undef u64SavedRetNanoTS
440	%undef u32ApicIdPlus
441	%ifdef NEED_TRANSACTION_ID
442	%ifdef ASYNC_GIP
443	%define u64SavedRetNanoTS r14
444	%define u32ApicIdPlus r15d
445	%endif
446	%endif
447
448	;
449	; The prolog.
450	;
451	push rbp
452	mov rbp, rsp
453	%ifdef ASM_CALL64_MSC
454	sub rsp, 50h+20h
455	%else
456	sub rsp, 50h
457	%endif
458	mov SavedRBX, rbx
459	mov SavedR12, r12
460	mov SavedR13, r13
461	%ifdef ASM_CALL64_MSC
462	mov SavedRDI, rdi
463	mov SavedRSI, rsi
464	mov pData, rcx
465	%else
466	;mov pData, rdi - already in rdi.
467	%endif
468	%ifdef SavedR14
469	mov SavedR14, r14
470	%endif
471	%ifdef SavedR15
472	mov SavedR15, r15
473	%endif
474
475
476	;;
477	;; Data fetch loop.
478	;; We take great pain ensuring that data consistency here.
479	;;
480	.ReadGip:
481
482	;
483	; Load pGip and calc pGipCPU, setting u32ApicIdPlus if necessary.
484	; Finding the GIP is fun...
485	;
486	%ifdef RT_OS_WINDOWS
487	%ifdef IMPORTED_SUPLIB
488	%ifdef IN_RING0
489	mov rax, qword IMP(g_SUPGlobalInfoPage)
490	mov pGip, rax
491	%else
492	mov pGip, [IMP(g_pSUPGlobalInfoPage) wrt rip]
493	mov pGip, [pGip]
494	%endif
495	%else
496	mov pGip, [NAME(g_pSUPGlobalInfoPage) wrt rip]
497	%endif
498	%else
499	%ifdef IN_RING0
500	mov rax, qword NAME(g_SUPGlobalInfoPage)
501	mov pGip, rax
502	%else
503	mov pGip, [rel NAME(g_pSUPGlobalInfoPage) wrt ..gotpcrel]
504	mov pGip, [pGip]
505	%endif
506	%endif
507	or pGip, pGip
508	jz .Rediscover
509	cmp dword [pGip + SUPGLOBALINFOPAGE.u32Magic], SUPGLOBALINFOPAGE_MAGIC
510	jne .Rediscover
511
512	%ifdef ASYNC_GIP
513	; u8ApicId = ASMGetApicId();
514	mov eax, 1
515	cpuid ; expensive
516	%ifdef NEED_TRANSACTION_ID
517	mov u32ApicIdPlus, ebx
518	%endif
519	; pGipCpu = &pGip->aCPU[pGip->aiCpuFromApicId[u8ApicId]];
520	shr ebx, 24
521	movzx eax, word [pGip + rbx * 2 + SUPGLOBALINFOPAGE.aiCpuFromApicId]
522	imul eax, SUPGIPCPU_size
523	lea pGipCPU, [pGip + rax + SUPGLOBALINFOPAGE.aCPUs]
524	%else
525	lea pGipCPU, [pGip + SUPGLOBALINFOPAGE.aCPUs]
526	%endif
527
528	%ifdef NEED_TRANSACTION_ID
529	;
530	; Serialized loading of u32TransactionId.
531	;
532	mov u32TransactionId, [pGipCPU + SUPGIPCPU.u32TransactionId]
533	%ifdef USE_LFENCE
534	lfence
535	%else
536	lock xor dword TmpVar, 0
537	%endif
538	%endif
539
540	;
541	; Load the data and TSC.
542	;
543	mov u32UpdateIntervalNS, [pGip + SUPGLOBALINFOPAGE.u32UpdateIntervalNS] ; before u64TSC
544	mov u32UpdateIntervalTSC, [pGipCPU + SUPGIPCPU.u32UpdateIntervalTSC]
545	rdtsc
546	mov u64PrevNanoTS, [pData + RTTIMENANOTSDATA.pu64Prev]
547	mov u64PrevNanoTS, [u64PrevNanoTS]
548	shl rdx, 32
549	%ifdef u64SavedRetNanoTS ; doing this here saves a tick or so.
550	mov u64SavedRetNanoTS, rax
551	or u64SavedRetNanoTS, rdx
552	%else
553	or rax, rdx ; rax is u64RetNanoTS.
554	%endif
555	mov u64CurNanoTS, [pGipCPU + SUPGIPCPU.u64NanoTS]
556	mov u64TSC, [pGipCPU + SUPGIPCPU.u64TSC]
557
558	%ifdef NEED_TRANSACTION_ID
559	;
560	; Check that the GIP and CPU didn't change.
561	;
562	; It is crucial that the rdtsc instruction has completed before
563	; we check the transaction id. The LOCK prefixed instruction with
564	; dependency on the RDTSC result should do the trick, I think.
565	; CPUID is serializing, so the async path is safe by default.
566	;
567	%ifdef ASYNC_GIP
568	mov eax, 1
569	cpuid
570	cmp u32ApicIdPlus, ebx
571	jne .ReadGip
572	%else
573	lock xor qword TmpVar, rax
574	%endif
575	cmp u32TransactionId, [pGipCPU + SUPGIPCPU.u32TransactionId]
576	jne .ReadGip
577	test u32TransactionId, 1
578	jnz .ReadGip
579	%ifdef u64SavedRetNanoTS
580	mov rax, u64SavedRetNanoTS ; rax is u64RetNanoTS.
581	%endif
582	%endif ; NEED_TRANSACTION_ID
583
584
585	;;
586	;; Calc the timestamp.
587	;;
588	; u64RetNanoTS -= u64TSC;
589	sub rax, u64TSC
590	xor edx, edx
591
592	; if (u64RetNanoTS > u32UpdateIntervalTSC) -> jump
593	cmp rax, u32UpdateIntervalTSC_64
594	ja .OverFlow
595	.ContinueCalcs: ; edx = 0; eax <= u32UpdateIntervalTSC
596	mul u32UpdateIntervalNS
597	div u32UpdateIntervalTSC
598
599	; u64RetNanoTS += u64CurNanoTS;
600	add rax, u64CurNanoTS
601
602
603	;;
604	;; Compare it with the previous one.
605	;;
606	; if (RT_LIKELY( u64RetNanoTS > u64PrevNanoTS
607	; && u64RetNanoTS < u64PrevNanoTS + UINT64_C(86000000000000) /* 24h */))
608	; /* Frequent - less than 24h since last call. */;
609	cmp rax, u64PrevNanoTS
610	jbe .DeltaPrevTooBig
611	mov ecx, 5
612	shl rcx, 44 ; close enough
613	add rcx, u64PrevNanoTS
614	cmp rax, rcx
615	jae .DeltaPrevTooBig
616
617
618	;;
619	;; Update the previous value.
620	;;
621	.Update:
622	; if (RT_LIKELY(ASMAtomicCmpXchgU64(&pData->u64Prev, u64RetNanoTS, u64PrevNanoTS)))
623	mov rbx, [pData + RTTIMENANOTSDATA.pu64Prev]
624	mov rcx, rax
625	mov rax, u64PrevNanoTS
626	lock cmpxchg [rbx], rcx
627	jnz .UpdateFailed
628
629	.Updated:
630	mov rax, rcx
631
632	.Done:
633	mov rbx, SavedRBX
634	mov r12, SavedR12
635	mov r13, SavedR13
636	%ifdef SavedR14
637	mov r14, SavedR14
638	%endif
639	%ifdef SavedR15
640	mov r15, SavedR15
641	%endif
642	%ifdef ASM_CALL64_MSC
643	mov rdi, SavedRDI
644	mov rsi, SavedRSI
645	%endif
646	leave
647	ret
648
649
650	;;
651	;; We've expired the interval, cap it. If we're here for the 2nd
652	;; time without any GIP update in-between, the checks against
653	;; pData->u64Prev below will force 1ns stepping.
654	;;
655	ALIGNCODE(16)
656	.OverFlow:
657	; u64RetNanoTS = u32UpdateIntervalTSC;
658	inc dword [pData + RTTIMENANOTSDATA.cExpired]
659	mov eax, u32UpdateIntervalTSC
660	jmp .ContinueCalcs
661
662
663	;;
664	;; u64DeltaPrev >= 24h
665	;;
666	;; rax = u64RetNanoTS (to be adjusted)
667	;;
668	ALIGNCODE(16)
669	.DeltaPrevTooBig:
670	; uint64_t u64DeltaPrev = u64RetNanoTS - u64PrevNanoTS;
671	mov rbx, rax
672	sub rbx, u64PrevNanoTS
673
674	; else if ( (int64_t)u64DeltaPrev <= 0
675	; && (int64_t)u64DeltaPrev + u32UpdateIntervalNS * 2 >= 0)
676	; {
677	; /* Occasional - u64NanoTS is in the recent 'past' relative the previous call. */
678	; pData->c1nsSteps++;
679	; u64RetNanoTS = u64PrevNanoTS + 1;
680	; }
681	test rbx, rbx
682	jg .DeltaPrevNotInRecentPast
683
684	lea rdx, [u32UpdateIntervalNS_64 + u32UpdateIntervalNS_64]
685	add rdx, rbx
686	js .DeltaPrevNotInRecentPast
687
688	; body
689	inc dword [pData + RTTIMENANOTSDATA.c1nsSteps]
690	lea rax, [u64PrevNanoTS + 1]
691	jmp .Update
692
693	; else if (!u64PrevNanoTS) /* We're resuming (see TMVirtualResume) / first call. */
694	; /* do nothing */;
695	.DeltaPrevNotInRecentPast:
696	or u64PrevNanoTS, u64PrevNanoTS
697	jz .Update
698
699	; else
700	; {
701	; /* Something has gone bust, if negative offset it's real bad. */
702	; rtTimeNanoTSInternalBitch(pVM,
703	; }
704
705	; call C function that does the bitching.
706	mov TmpVar, rax
707	mov TmpVar2, pData
708
709	%ifdef ASM_CALL64_MSC
710	mov rcx, pData ; param 1 - pData
711	mov rdx, rax ; param 2 - u64RetNanoTS
712	mov r8, rbx ; param 3 - u64DeltaPrev
713	mov r9, u64PrevNanoTS ; param 4 - u64PrevNanoTS
714	%else
715	;mov rdi, pData - already in rdi; param 1 - pData
716	mov rsi, rax ; param 2 - u64RetNanoTS
717	mov rdx, rbx ; param 3 - u64DeltaPrev
718	mov rcx, u64PrevNanoTS ; param 4 - u64PrevNanoTS
719	%endif
720	call qword [pData + RTTIMENANOTSDATA.pfnBad]
721
722	mov rax, TmpVar
723	mov pData, TmpVar2
724	jmp .Update
725
726
727	;;
728	;; Attempt updating the previous value, provided we're still ahead of it.
729	;;
730	;; There is no point in recalculating u64NanoTS because we got preempted or if
731	;; we raced somebody while the GIP was updated, since these are events
732	;; that might occur at any point in the return path as well.
733	;;
734	;; rax = *pData->u64Prev;
735	;; rcx = u64RetNanoTS
736	;;
737	ALIGNCODE(16)
738	.UpdateFailed:
739	lock inc dword [pData + RTTIMENANOTSDATA.cUpdateRaces]
740	; for (i = 0; i < 10; i++)
741	mov edx, 10
742	.UpdateLoop:
743	; if (u64PrevNanoTS >= u64RetNanoTS)
744	; break;
745	cmp rax, rcx
746	jge .Updated
747	.UpdateLoopLess:
748	; retry
749	lock cmpxchg [rbx], rcx
750	jz .Updated
751	dec edx
752	jnz .UpdateLoop
753	jmp .Updated
754
755
756	;;
757	;; The GIP is seemingly invalid, redo the discovery.
758	;;
759	.Rediscover:
760	%ifdef ASM_CALL64_MSC
761	mov rcx, pData
762	%else
763	; mov rdi, pData - already in rdi
764	%endif
765	call [pData + RTTIMENANOTSDATA.pfnRediscover]
766	jmp .Done
767
768
769	;
770	; Cleanup variables
771	;
772	%undef SavedRBX
773	%undef SavedR12
774	%undef SavedR13
775	%undef SavedR14
776	%undef SavedR15
777	%undef SavedRDI
778	%undef SavedRSI
779	%undef pData
780	%undef TmpVar
781	%undef u64TSC
782	%undef pGip
783	%undef pGipCPU
784	%undef u32TransactionId
785	%undef u64CurNanoTS
786	%undef u64PrevNanoTS
787	%undef u32UpdateIntervalTSC
788	%undef u32UpdateIntervalTSC_64
789	%undef u32UpdateIntervalNS
790	%undef u64SavedRetNanoTS
791	%undef u32ApicIdPlus
792
793	%endif ; AMD64
794	ENDPROC rtTimeNanoTSInternalAsm
795
796
797

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