Sinipelto/banan-os
1
0
Fork 0
forked from Bananymous/banan-os
Code Pull Requests Activity

Kernel/LibC: Use builtin functions over inline asm

Browse Source 
Getting flags and saving/restoring sse state and reading TSC can be done
using compiler builtins
This commit is contained in:
Bananymous
2026-01-09 15:19:19 +02:00
parent a9ceab0415
commit 74f70ae4bd
5 changed files with 14 additions and 39 deletions
Download Patch File Download Diff File Expand all files Collapse all files

11
kernel/kernel/Timer/Timer.cpp
View File

@@ -80,13 +80,6 @@ namespace Kernel
{
// take 5x 50 ms samples and use the median value
const auto read_tsc =
[]() -> uint64_t {
uint32_t high, low;
asm volatile("lfence; rdtsc" : "=d"(high), "=a"(low));
return (static_cast<uint64_t>(high) << 32) | low;
};
constexpr size_t tsc_sample_count = 5;
constexpr size_t tsc_sample_ns = 50'000'000;
@@ -95,10 +88,10 @@ namespace Kernel
{
const auto start_ns = m_timer->ns_since_boot();
const auto start_tsc = read_tsc();
const auto start_tsc = __builtin_ia32_rdtsc();
while (m_timer->ns_since_boot() < start_ns + tsc_sample_ns)
Processor::pause();
const auto stop_tsc = read_tsc();
const auto stop_tsc = __builtin_ia32_rdtsc();
const auto stop_ns = m_timer->ns_since_boot();