// ke_cpu.c - bootstrap/per-CPU state plumbing
#include <string.h>
#include <kernel/ke_cpu.h>

#define BOOTSTRAP_CPU_STACK_SIZE 0x4000u

KCPU gCpus[KE_MAX_CPUS];
uint32_t gCpuCount = 0;

static uint8_t gBootstrapCpuStack[BOOTSTRAP_CPU_STACK_SIZE];

void KeInitializeBootstrapCpu(void) {
    memset(gCpus, 0, sizeof(gCpus));

    KCPU* cpu = &gCpus[0];
    cpu->CpuIndex = 0;
    cpu->LapicId = 0;
    cpu->Present = 1;
    cpu->Online = 1;
    cpu->IsBsp = 1;
    cpu->CurrentIrql = PASSIVE_LEVEL;
    cpu->InterruptDepth = 0;
    cpu->ReschedulePending = 0;
    cpu->KernelStack = gBootstrapCpuStack;
    cpu->KernelStackTop = (uintptr_t)(gBootstrapCpuStack + sizeof(gBootstrapCpuStack));
    memset(&cpu->Tss, 0, sizeof(cpu->Tss));
    cpu->Tss.IoMapBase = sizeof(TSS64);
    cpu->Tss.RSP0 = cpu->KernelStackTop;

    gCpuCount = 1;
}

KCPU* KeGetCurrentCpu(void) {
    // SMP phase 1: only CPU0 is online.  Later this becomes LAPIC-ID or
    // per-CPU-base based lookup once the bootloader parks APs for us.
    return &gCpus[0];
}

KCPU* KeGetCpuByIndex(uint32_t index) {
    if (index >= KE_MAX_CPUS)
        return (KCPU*)0;
    return &gCpus[index];
}

uint32_t KeGetCurrentCpuIndex(void) {
    return KeGetCurrentCpu()->CpuIndex;
}

TSS64* KeGetCurrentTss(void) {
    return &KeGetCurrentCpu()->Tss;
}