7 files changed, 102 insertions, 0 deletions
diff --git a/src/loader/inc/a20.h b/src/loader/inc/a20.h
new file mode 100644
index 0000000..705ada0
--- /dev/null
+++ b/src/loader/inc/a20.h
@@ -0,0 +1,10 @@
+// MIT License, Copyright (c) 2021 Marvin Borner
+
+#ifndef A20_H
+#define A20_H
+
+#include <def.h>
+
+void a20_enable(void);
+
+#endif
diff --git a/src/loader/inc/cpu.h b/src/loader/inc/cpu.h
index 0236002..4fa7d0c 100644
--- a/src/loader/inc/cpu.h
+++ b/src/loader/inc/cpu.h
@@ -13,4 +13,7 @@ void outb(u16 port, u8 data);
 void outw(u16 port, u16 data);
 void outl(u16 port, u32 data);
 
+u16 mminw(u32 addr);
+void mmoutw(u32 addr, u16 value);
+
 #endif
diff --git a/src/loader/inc/def.h b/src/loader/inc/def.h
index a8ee30b..e42c372 100644
--- a/src/loader/inc/def.h
+++ b/src/loader/inc/def.h
@@ -28,6 +28,7 @@ typedef __builtin_va_list va_list;
 #define STRINGIFY_PARAM(a) #a
 #define STRINGIFY(a) STRINGIFY_PARAM(a)
 
+#define REAL __attribute__((section(".realmode")))
 #define PACKED __attribute__((packed))
 
 #endif
diff --git a/src/loader/inc/gdt.h b/src/loader/inc/gdt.h
new file mode 100644
index 0000000..1ff20b7
--- /dev/null
+++ b/src/loader/inc/gdt.h
@@ -0,0 +1,25 @@
+// MIT License, Copyright (c) 2021 Marvin Borner
+
+#ifndef GDT_H
+#define GDT_H
+
+#include <def.h>
+
+struct gdtr {
+	u16 limit;
+	u32 ptr;
+	u32 pad;
+} PACKED;
+
+struct gdt_desc {
+	u16 limit;
+	u16 base_low;
+	u8 base_mid;
+	u8 access;
+	u8 granularity;
+	u8 base_hi;
+} PACKED;
+
+extern struct gdtr gdt;
+
+#endif
diff --git a/src/loader/inc/int.h b/src/loader/inc/int.h
index ccd9ea8..8336cd8 100644
--- a/src/loader/inc/int.h
+++ b/src/loader/inc/int.h
@@ -43,6 +43,8 @@ struct idt_ptr {
 	void *base;
 } PACKED;
 
+extern struct idt_ptr idt;
+
 void idt_install(void);
 void int_event_handler_add(u32 int_no, void (*handler)(void));
 
diff --git a/src/loader/inc/mem.h b/src/loader/inc/mem.h
new file mode 100644
index 0000000..7153465
--- /dev/null
+++ b/src/loader/inc/mem.h
@@ -0,0 +1,32 @@
+// MIT License, Copyright (c) 2021 Marvin Borner
+
+#ifndef MEM_H
+#define MEM_H
+
+#include <def.h>
+
+enum mem_entry_type {
+	MEM_NONE,
+	MEM_USABLE,
+	MEM_RESERVED,
+	MEM_RECLAIMABLE,
+	MEM_ACPI_NVS,
+	MEM_UNUSABLE,
+};
+
+// Generalised memory map entry struct
+struct mem_entry {
+	u32 base;
+	u32 length;
+	u32 type;
+};
+
+struct mem_map {
+	struct mem_entry *entry;
+	u32 count;
+};
+
+void mem_map(void);
+struct mem_map *mem_map_get(void);
+
+#endif
diff --git a/src/loader/inc/rem.h b/src/loader/inc/rem.h
new file mode 100644
index 0000000..61eb30a
--- /dev/null
+++ b/src/loader/inc/rem.h
@@ -0,0 +1,29 @@
+// MIT License, Copyright (c) 2021 Marvin Borner
+// Real mode emulation - Implementation by Napalm (see rem.asm)
+
+#ifndef REM_H
+#define REM_H
+
+#include <def.h>
+
+#define EFLAGS_CF (1 << 0) // Carry flag
+#define EFLAGS_ZF (1 << 6) // Zero flag
+
+struct rem_regs {
+	u16 gs;
+	u16 fs;
+	u16 es;
+	u16 ds;
+	u32 eflags;
+	u32 ebp;
+	u32 edi;
+	u32 esi;
+	u32 edx;
+	u32 ecx;
+	u32 ebx;
+	u32 eax;
+} PACKED;
+
+void rem_int(u8 int_num, struct rem_regs *out_regs, struct rem_regs *in_regs);
+
+#endif