vpx_ports/x86.h: sync with aom_ports/x86.h

adds a few comments and makes the file ascii:
854b2766a Replace non-ASCII characters

Change-Id: I6c2d76b293158bcad9f1ded7a91a81bda1e700fb

diff --git a/vpx_ports/x86.h b/vpx_ports/x86.h
index ad3da84aca9ca150f18283e76250dd8a7e66d329..4d5391b78ddfba38acd8c028dae30bfbed4ff0c4 100644 (file)
--- a/vpx_ports/x86.h
+++ b/vpx_ports/x86.h
@@ -242,7 +242,7 @@ static INLINE int x86_simd_caps(void) {
 // x86_readtsc directly, but prevent the CPU's out-of-order execution from
 // affecting the measurement (by having earlier/later instructions be evaluated
 // in the time interval). See the white paper, "How to Benchmark Code
-// Execution Times on Intel® IA-32 and IA-64 Instruction Set Architectures" by
+// Execution Times on Intel(R) IA-32 and IA-64 Instruction Set Architectures" by
 // Gabriele Paoloni for more information.
 //
 // If you are timing a large function (CPU time > a couple of seconds), use
@@ -308,6 +308,7 @@ static INLINE unsigned int x86_readtscp(void) {
 
 static INLINE unsigned int x86_tsc_start(void) {
   unsigned int reg_eax, reg_ebx, reg_ecx, reg_edx;
+  // This call should not be removed. See function notes above.
   cpuid(0, 0, reg_eax, reg_ebx, reg_ecx, reg_edx);
   // Avoid compiler warnings on unused-but-set variables.
   (void)reg_eax;
@@ -320,6 +321,7 @@ static INLINE unsigned int x86_tsc_start(void) {
 static INLINE unsigned int x86_tsc_end(void) {
   uint32_t v = x86_readtscp();
   unsigned int reg_eax, reg_ebx, reg_ecx, reg_edx;
+  // This call should not be removed. See function notes above.
   cpuid(0, 0, reg_eax, reg_ebx, reg_ecx, reg_edx);
   // Avoid compiler warnings on unused-but-set variables.
   (void)reg_eax;