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Kernel/LibC: Use builtin functions over inline asm

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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
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18
kernel/kernel/Processor.cpp
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@@ -304,29 +304,15 @@ namespace Kernel
void Processor::update_tsc()
{
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;
};
auto& sgettime = shared_page().cpus[current_index()].gettime_local;
sgettime.seq = sgettime.seq + 1;
sgettime.last_ns = SystemTimer::get().ns_since_boot_no_tsc();
sgettime.last_tsc = read_tsc();
sgettime.last_tsc = __builtin_ia32_rdtsc();
sgettime.seq = sgettime.seq + 1;
}
uint64_t Processor::ns_since_boot_tsc()
{
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;
};
const auto& shared_page = Processor::shared_page();
const auto& sgettime = shared_page.gettime_shared;
const auto& lgettime = shared_page.cpus[current_index()].gettime_local;
@@ -334,7 +320,7 @@ namespace Kernel
auto state = get_interrupt_state();
set_interrupt_state(InterruptState::Disabled);
const auto current_ns = lgettime.last_ns + (((read_tsc() - lgettime.last_tsc) * sgettime.mult) >> sgettime.shift);
const auto current_ns = lgettime.last_ns + (((__builtin_ia32_rdtsc() - lgettime.last_tsc) * sgettime.mult) >> sgettime.shift);
set_interrupt_state(state);