diff --git a/paw/stos/head/drivers/acpi/tables.h b/paw/stos/head/drivers/acpi/tables.h
new file mode 100644
index 0000000..8e8a904
--- /dev/null
+++ b/paw/stos/head/drivers/acpi/tables.h
@@ -0,0 +1,131 @@
+/*
+ * Copyright (c) 2026, Chloe M.
+ * Provided under the BSD-3 clause.
+ *
+ * Description: ACPI definitions
+ * Author:      Chloe M.
+ */
+
+#ifndef _ACPI_TABLES_H_
+#define _ACPI_TABLES_H_ 1
+
+#include <stdef.h>
+
+/* MADT APIC header types */
+#define APIC_TYPE_LOCAL_APIC            0
+#define APIC_TYPE_IO_APIC               1
+#define APIC_TYPE_INTERRUPT_OVERRIDE    2
+
+#define OEMID_SIZE 6
+
+typedef struct PACKED {
+    CHAR Signature[4];
+    ULONG Length;
+    UCHAR Revision;
+    UCHAR Checksum;
+    CHAR Oemid[OEMID_SIZE];
+    CHAR OemTableId[8];
+    ULONG OemRevision;
+    ULONG CreatorId;
+    ULONG CreatorRevision;
+} ACPI_HEADER;
+
+typedef struct PACKED {
+    UQUAD Signature;
+    UCHAR Checksum;
+    CHAR Oemid[OEMID_SIZE];
+    UCHAR Revision;
+    ULONG RsdtAddr;
+
+    /* Reserved if revision < 2 */
+    ULONG Length;
+    UQUAD XsdtAddr;
+    UCHAR ExtChecksum;
+    UCHAR Reserved[3];
+} ACPI_RSDP;
+
+/*
+ * XSDT or RSDT depending on the revision within the
+ * header
+ */
+typedef struct PACKED {
+    ACPI_HEADER Header;
+    ULONG Tables[];
+} ACPI_ROOT_SDT;
+
+typedef struct PACKED {
+    ACPI_HEADER Header;
+    ULONG LapicAddr;
+    ULONG Flags;
+} ACPI_MADT;
+
+typedef struct PACKED {
+    UCHAR Type;
+    UCHAR Length;
+} ACPI_APIC_HEADER;
+
+typedef struct PACKED {
+    ACPI_APIC_HEADER Header;
+    UCHAR ProcessorId;
+    UCHAR ApicId;
+    ULONG Flags;
+} ACPI_LOCAL_APIC;
+
+typedef struct PACKED {
+    UCHAR AddressSpaceId;
+    UCHAR RegisterBitWidth;
+    UCHAR RegisterBitOffset;
+    UCHAR Reserved;
+    UQUAD Address;
+} ACPI_GAS;
+
+/*
+ * ACPI Address Space ID definitions for GAS
+ *
+ * See section 5.2.3.2 of the ACPI software programming
+ * manual.
+ *
+ * XXX: 0x0B->0x7E is reserved as well as 0x80->0xBF
+ *      and 0xC0->0xFF is OEM defined. Values other than
+ *      the ones specified below are either garbage or
+ *      OEM specific values.
+ */
+#define ACPI_GAS_SYSMEM   0x00      /* System memory space */
+#define ACPI_GAS_SYSIO    0x01      /* System I/O space */
+#define ACPI_GAS_PCICONF  0x02      /* PCI configuration space */
+#define ACPI_GAS_EC       0x03      /* Embedded controller */
+#define ACPI_GAS_SMBUS    0x04      /* System management bus */
+#define ACPI_GAS_CMOS     0x05      /* System CMOS */
+#define ACPI_GAS_PCIBAR   0x06      /* PCI BAR target */
+#define ACPI_GAS_IPMI     0x07      /* IPMI (sensor monitoring) */
+#define ACPI_GAS_GPIO     0x08      /* General Purpose I/O */
+#define ACPI_GAS_GSBUS    0x09      /* GenericSerialBus */
+#define ACPI_GAS_PLATCOM  0x0A      /* Platform Communications Channel */
+
+/*
+ * ACPI address size definitions for GAS
+ *
+ * See section 5.2.3.2 of the ACPI software programming
+ * manual.
+ */
+#define ACPI_GAS_UNDEF  0   /* Undefined (legacy reasons) */
+#define ACPI_GAS_BYTE   1   /* Byte access */
+#define ACPI_GAS_WORD   2   /* Word access */
+#define ACPI_GAS_DWORD  3   /* Dword access */
+#define ACPI_GAS_QWORD  4   /* Qword access */
+
+typedef struct PACKED {
+    ACPI_HEADER Header;
+    UCHAR HardwareRevId;
+    UCHAR ComparatorCount   : 5;
+    UCHAR CounterSize       : 1;
+    UCHAR Reserved          : 1;
+    UCHAR LegacyReplacement : 1;
+    USHORT PciVendorId;
+    ACPI_GAS Gas;
+    UCHAR HpetNumber;
+    USHORT MinimumTick;
+    UCHAR PageProtection;
+} ACPI_HPET;
+
+#endif  /* _ACPI_TABLES_H_ */