acpi detection

Makefile

@@ -1,7 +1,8 @@
 CXXFLAGS := -m32 -ggdb -g3 -O0 -fno-pic -ffreestanding -fno-rtti -fno-exceptions -std=c++23
 LDFLAGS := -m32 -static -T link.ld -ffreestanding -nostdlib
 
-CXXFILES := boot.cpp \
+CXXFILES := acpi.cpp \
+	boot.cpp \
         gdt.cpp \
         idt.cpp \
         memory.cpp \

acpi.cpp

@@ -0,0 +1,51 @@
+#include "textoutput.hpp"
+
+#include <cstdint>
+
+extern TextOutput& term;
+extern std::uint32_t *acpiRsdp;
+extern std::uint32_t *acpiRsdpV2;
+
+struct XSDP {
+   char Signature[8];
+   std::uint8_t Checksum;
+   char OEMID[6];
+   std::uint8_t Revision;
+   std::uint32_t RsdtAddress;      // deprecated since version 2.0
+
+   // v2 only!
+   std::uint32_t Length;
+   std::uint64_t XsdtAddress;
+   std::uint8_t ExtendedChecksum;
+   std::uint8_t reserved[3];
+} __attribute__ ((packed));
+
+struct SDTHeader {
+    char Signature[4];
+    std::uint32_t Length;
+    std::uint8_t Revision;
+    std::uint8_t Checksum;
+    char OEMID[6];
+    char OEMTableID[8];
+    std::uint32_t OEMRevision;
+    std::uint32_t CreatorID;
+    std::uint32_t CreatorRevision;
+};
+
+static XSDP *rsdp = nullptr;
+
+void acpi_initialize()
+{
+    if (acpiRsdp) {
+        term.write("ACPI v1 detected.\n");
+        rsdp = reinterpret_cast<XSDP *>(acpiRsdp);
+    } else if (acpiRsdpV2) {
+        term.write("ACPI v2 detected, treating as v1.\n");
+        rsdp = reinterpret_cast<XSDP *>(acpiRsdpV2);
+    }
+
+    //if (rsdp) {
+    //    auto sdt = reinterpret_cast<SDTHeader *>(rsdp->RsdtAddress);
+    //}
+}
+

acpi.hpp

@@ -0,0 +1,7 @@
+#ifndef ACPI_HPP
+#define ACPI_HPP
+
+void acpi_initialize();
+
+#endif // ACPI_HPP
+

boot.cpp

@@ -3,43 +3,6 @@
 
 extern void kernel_main();
 
-struct multiboot2
-{
-    static constexpr std::uint32_t MAGIC    = 0xE85250D6;
-    static constexpr std::uint32_t FLAGS    = 0;
-    static constexpr std::uint32_t LENGTH   = 16;
-    static constexpr std::uint32_t CHECKSUM = -(MAGIC + FLAGS + LENGTH);
-
-    alignas(8)
-    std::uint32_t magic = MAGIC;
-    std::uint32_t flags = FLAGS;
-    std::uint32_t length = LENGTH;
-    std::uint32_t checksum = CHECKSUM;
-} __attribute__((packed));
-
-struct multiboot2_tag
-{
-    alignas(8)
-    std::uint16_t id;
-    std::uint16_t flags;
-    std::uint32_t length;
-    std::uint32_t data[];
-} __attribute__((packed));
-
-__attribute__((section(".multiboot2")))
-multiboot2 multibootHeader;
-
-__attribute__((section(".multiboot2")))
-multiboot2_tag multibootTagInfoRequest = { 
-    1, 0, sizeof(multiboot2_tag) + sizeof(std::uint32_t),
-    {4}
-};
-
-__attribute__((section(".multiboot2")))
-multiboot2_tag multibootTagEnd = { 
-    0, 0, sizeof(multiboot2_tag), {}
-};
-
 alignas(16)
 std::array<std::uint8_t, 16384> stack;
 

kernel.cpp

@@ -1,3 +1,4 @@
+#include "acpi.hpp"
 #include "gdt.hpp"
 #include "idt.hpp"
 #include "memory.hpp"
@@ -26,6 +27,7 @@ void kernel_main(void)
         for (;;);
     });
 
+    acpi_initialize();
     memory_initialize();
     gdt_initialize();
     pic_initialize();

multiboot.cpp

@@ -4,11 +4,50 @@
 
 extern TextOutput& term;
 
+struct multiboot2
+{
+    static constexpr std::uint32_t MAGIC    = 0xE85250D6;
+    static constexpr std::uint32_t FLAGS    = 0;
+    static constexpr std::uint32_t LENGTH   = 16;
+    static constexpr std::uint32_t CHECKSUM = -(MAGIC + FLAGS + LENGTH);
+
+    alignas(8)
+    std::uint32_t magic = MAGIC;
+    std::uint32_t flags = FLAGS;
+    std::uint32_t length = LENGTH;
+    std::uint32_t checksum = CHECKSUM;
+} __attribute__((packed));
+
+struct multiboot2_tag
+{
+    alignas(8)
+    std::uint16_t id;
+    std::uint16_t flags;
+    std::uint32_t length;
+    std::uint32_t data[];
+} __attribute__((packed));
+
+__attribute__((section(".multiboot2")))
+multiboot2 multibootHeader;
+
+__attribute__((section(".multiboot2")))
+multiboot2_tag multibootTagInfoRequest = {
+    1, 0, sizeof(multiboot2_tag) + sizeof(std::uint32_t),
+    {4}
+};
+
+__attribute__((section(".multiboot2")))
+multiboot2_tag multibootTagEnd = {
+    0, 0, sizeof(multiboot2_tag), {}
+};
+
 std::uint32_t multiboot_magic;
 std::uint32_t *multiboot_ptr;
 
 std::uint32_t lowerMem = 0;
 std::uint32_t upperMem = 0;
+std::uint32_t *acpiRsdp = nullptr;
+std::uint32_t *acpiRsdpV2 = nullptr;
 
 bool multiboot_initialize()
 {
@@ -24,9 +63,19 @@ bool multiboot_initialize()
         term.write(ptr[0]);
         term.write(", ");
 
-        if (ptr[0] == 4) {
+        switch (ptr[0]) {
+        case 4:
             lowerMem = ptr[2] * 1024;
             upperMem = ptr[3] * 1024;
+            break;
+        case 14:
+            acpiRsdp = ptr + 2;
+            break;
+        case 15:
+            acpiRsdpV2 = ptr + 2;
+            break;
+        default:
+            break;
         }
     
         auto next = reinterpret_cast<std::uintptr_t>(ptr);