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Fix detection of VFP support on Nexus One.

BUG=none
TEST=none

Code review URL: http://codereview.chromium.org/5664004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5952 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
ager@chromium.org 2010-12-08 18:08:23 +00:00
parent a5c8cab793
commit 649a471089
1 changed files with 14 additions and 15 deletions
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29
src/platform-linux.cc
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@ -134,9 +134,7 @@ static bool CPUInfoContainsString(const char * search_string) {
}
bool OS::ArmCpuHasFeature(CpuFeature feature) {
const int max_items = 2;
const char* search_strings[max_items] = { NULL, NULL };
int search_items = 0;
const char* search_string = NULL;
// Simple detection of VFP at runtime for Linux.
// It is based on /proc/cpuinfo, which reveals hardware configuration
// to user-space applications. According to ARM (mid 2009), no similar
@ -144,25 +142,26 @@ bool OS::ArmCpuHasFeature(CpuFeature feature) {
// so it's up to individual OSes to provide such.
switch (feature) {
case VFP3:
search_strings[0] = "vfpv3";
// Some old kernels will report vfp for A8, not vfpv3, so we check for
// A8 explicitely. The cpuinfo file report the CPU Part which for Cortex
// A8 is 0xc08.
search_strings[1] = "0xc08";
search_items = 2;
ASSERT(search_items <= max_items);
search_string = "vfpv3";
break;
case ARMv7:
search_strings[0] = "ARMv7" ;
search_items = 1;
ASSERT(search_items <= max_items);
search_string = "ARMv7";
break;
default:
UNREACHABLE();
}
for (int i = 0; i < search_items; ++i) {
if (CPUInfoContainsString(search_strings[i])) {
if (CPUInfoContainsString(search_string)) {
return true;
}
if (feature == VFP3) {
// Some old kernels will report vfp not vfpv3. Here we make a last attempt
// to detect vfpv3 by checking for vfp *and* neon, since neon is only
// available on architectures with vfpv3.
// Checking neon on its own is not enough as it is possible to have neon
// without vfp.
if (CPUInfoContainsString("vfp") && CPUInfoContainsString("neon")) {
return true;
}
}