| ; Copyright 2019 Google LLC |
| ; |
| ; Licensed under both the 3-Clause BSD License and the GPLv2, found in the |
| ; LICENSE and LICENSE.GPL-2.0 files, respectively, in the root directory. |
| ; |
| ; SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 |
| |
| .model flat |
| |
| ; Enable SSE so we can use LFENCE |
| .XMM |
| |
| .code |
| |
| ; See measurereadlatency_x86.S for the commented and formatted version. |
| public _MeasureReadLatency |
| _MeasureReadLatency: |
| push ebp |
| mov ebp, esp |
| push ebx |
| push esi |
| push edi |
| mov ebx, dword ptr [ebp+8] |
| mfence |
| lfence |
| rdtsc |
| mov edi, eax |
| mov esi, edx |
| lfence |
| mov al, byte ptr [ebx] |
| lfence |
| rdtsc |
| sub eax, edi |
| sbb edx, esi |
| pop edi |
| pop esi |
| pop ebx |
| pop ebp |
| ret |
| |
| end |
