feat: make kernel architecture-agnostic; primitive work on arm port

kernel/src/Arch/x86_64/Acpi/S3State.hpp

@@ -0,0 +1,30 @@
+/*
+    * S3State.hpp
+    * CPU state saved across S3 by S3Wake.asm
+    * Copyright (c) 2026 Daniel Hammer
+*/
+
+#pragma once
+#include <cstdint>
+
+namespace Hal {
+    namespace AcpiSleep {
+
+        // ============================================================================
+        // Layout must match S3Wake.asm offsets exactly.
+        // No FPU/SSE state — the kernel is compiled with -mno-sse.
+        struct CpuState {
+            uint64_t Rax, Rbx, Rcx, Rdx;   // 0x00 - 0x18
+            uint64_t Rsi, Rdi, Rbp, Rsp;   // 0x20 - 0x38
+            uint64_t R8, R9, R10, R11;     // 0x40 - 0x58
+            uint64_t R12, R13, R14, R15;   // 0x60 - 0x78
+            uint64_t Rflags;               // 0x80
+            uint64_t Rip;                  // 0x88
+            uint64_t Cr3;                  // 0x90
+            uint64_t Cr0, Cr4;             // 0x98, 0xA0
+            uint8_t  GdtPtr[10];           // 0xA8
+            uint8_t  IdtPtr[10];           // 0xB2
+        } __attribute__((aligned(16)));
+
+    };
+};