diff --git a/src/arch/i386/gdt.h b/src/arch/i386/gdt.h
index 68b527e..9f13152 100644
--- a/src/arch/i386/gdt.h
+++ b/src/arch/i386/gdt.h
@@ -23,14 +23,65 @@ typedef struct _GDTTable
 	unsigned int prot;
 } GDTTable;
 
+#pragma pack(1)
+typedef struct _TSS
+{
+	uint16_t link;
+	uint16_t __padding0;
+	uint32_t esp0;
+	uint16_t ss0;
+	uint16_t __padding1;
+	uint32_t esp1;
+	uint16_t ss1;
+	uint16_t __padding2;
+	uint32_t esp2;
+	uint16_t ss2;
+	uint16_t __padding3;
+	uint32_t cr3;
+	uint32_t eip;
+	uint32_t eflags;
+	uint32_t eax;
+	uint32_t ecx;
+	uint32_t edx;
+	uint32_t ebx;
+	uint32_t esp;
+	uint32_t ebp;
+	uint32_t esi;
+	uint32_t edi;
+	uint16_t es;
+	uint16_t __padding4;
+	uint16_t cs;
+	uint16_t __padding5;
+	uint16_t ss;
+	uint16_t __padding6;
+	uint16_t ds;
+	uint16_t __padding7;
+	uint16_t fs;
+	uint16_t __padding8;
+	uint16_t gs;
+	uint16_t __padding9;
+	uint16_t ldtr;
+	uint16_t __padding10;
+	uint16_t __padding11;
+	uint16_t iopb;
+	uint32_t ssp;
+} TSS;
+#pragma pack()
+
+
+/* constants */
+# define GDT_SYSTEM_TYPE_LDT	0x2
+# define GDT_SYSTEM_TYPE_TSS	0x9
+
 
 /* prototypes */
 GDT * gdt_init(void);
-int gdt_init_table(GDTTable const * table, size_t count);
+int gdt_init_table(GDTTable const * table, size_t table_cnt, size_t tss_cnt);
 
 
 /* useful */
 int gdt_append(GDT * gdt, vaddr_t base, size_t size, unsigned int prot);
+int gdt_append_system(GDT * gdt, void * base, size_t size, unsigned int type);
 
 void gdt_apply(GDT * gdt);
 
diff --git a/src/kernel/multiboot.c b/src/kernel/multiboot.c
index 434b47c..d6f5f7e 100644
--- a/src/kernel/multiboot.c
+++ b/src/kernel/multiboot.c
@@ -1,5 +1,5 @@
 /* $Id$ */
-/* Copyright (c) 2018-2019 Pierre Pronchery <khorben@defora.org> */
+/* Copyright (c) 2018-2025 Pierre Pronchery <khorben@defora.org> */
 /* This file is part of DeforaOS uKernel */
 
 
@@ -92,7 +92,7 @@ int multiboot(const ukMultibootInfo * mi)
 	if(_arch_setgdt64(_gdt_4gb, sizeof(_gdt_4gb) / sizeof(*_gdt_4gb)) != 0)
 #else
 	if(gdt_init_table((const GDTTable *)&_gdt_4gb,
-				sizeof(_gdt_4gb) / sizeof(*_gdt_4gb)) != 0)
+				sizeof(_gdt_4gb) / sizeof(*_gdt_4gb), 1) != 0)
 #endif
 	{
 		puts("Could not setup the GDT");
diff --git a/src/loader/gdt.c b/src/loader/gdt.c
index bfa5da1..a11101e 100644
--- a/src/loader/gdt.c
+++ b/src/loader/gdt.c
@@ -19,8 +19,8 @@
 
 /* access */
 # define GDT_ACCESS_SET			0x01
-# define GDT_ACCESS_RW			0x02
-# define GDT_ACCESS_X			0x08
+# define GDT_ACCESS_PROT_RW		0x02
+# define GDT_ACCESS_PROT_X		0x08
 # define GDT_ACCESS_SEGMENT		0x10
 # define GDT_ACCESS_RING(level)		((level) << 5)
 # define GDT_ACCESS_PRESENT		0x80
@@ -48,6 +48,21 @@ typedef struct _GDTEntry
 } GDTEntry;
 #pragma pack()
 
+#pragma pack(1)
+typedef struct _LDT
+{
+	uint8_t limit0;
+	uint8_t limit1;
+	uint8_t base0;
+	uint8_t base1;
+	uint8_t base2;
+	uint8_t access;
+	unsigned int limit2:4;
+	unsigned int flags:4;
+	uint8_t base3;
+} LDT;
+#pragma pack()
+
 struct _GDT
 {
 	GDTEntry entries[GDT_ENTRIES_MAX];
@@ -58,9 +73,13 @@ struct _GDT
 /* prototypes */
 extern void __arch_setgdt(GDTEntry const * entries, size_t count);
 
+static int _gdt_append_entry(GDT * gdt, vaddr_t base, uint32_t limit,
+		uint8_t access, uint8_t flags);
+
 
 /* variables */
 static GDT _gdt;
+static TSS _tss;
 
 
 /* functions */
@@ -74,17 +93,27 @@ GDT * gdt_init(void)
 
 
 /* gdt_init_table */
-int gdt_init_table(GDTTable const * table, size_t count)
+int gdt_init_table(GDTTable const * table, size_t table_cnt, size_t tss_cnt)
 {
 	int ret = 0;
 	GDT * gdt;
 	size_t i;
 
 	gdt = gdt_init();
-	for(i = 0; i < count; i++)
+	for(i = 0; i < table_cnt; i++)
 		if((ret = gdt_append(gdt, table[i].base, table[i].size,
 						table[i].prot)) != 0)
 			return ret;
+	/* set the TSS */
+	if(tss_cnt > 1)
+	{
+		errno = ENOSYS;
+		return -1;
+	}
+	else if(tss_cnt == 1 && (ret = gdt_append_system(gdt, &_tss,
+					sizeof(_tss), GDT_SYSTEM_TYPE_TSS))
+			!= 0)
+		return ret;
 	gdt_apply(gdt);
 	return 0;
 }
@@ -94,10 +123,9 @@ int gdt_init_table(GDTTable const * table, size_t count)
 /* gdt_append */
 int gdt_append(GDT * gdt, vaddr_t base, size_t size, unsigned int prot)
 {
-	GDTEntry * entry;
 	uint32_t limit;
-	uint8_t access = GDT_ACCESS_PRESENT
-		| GDT_ACCESS_SEGMENT | GDT_ACCESS_RING(0);
+	uint8_t access = GDT_ACCESS_SEGMENT | GDT_ACCESS_PRESENT
+		| GDT_ACCESS_RING(0);
 	uint8_t flags = GDT_FLAG_PROTECTED_MODE;
 
 	/* check for errors */
@@ -106,9 +134,7 @@ int gdt_append(GDT * gdt, vaddr_t base, size_t size, unsigned int prot)
 		errno = ERANGE;
 		return -1;
 	}
-	if(gdt->entries_cnt >= sizeof(gdt->entries) / sizeof(*gdt->entries)
-			|| size > ULONG_MAX
-			|| ULONG_MAX - size < base)
+	if(size > ULONG_MAX || ULONG_MAX - size < base)
 	{
 		errno = ENOMEM;
 		return -1;
@@ -120,41 +146,72 @@ int gdt_append(GDT * gdt, vaddr_t base, size_t size, unsigned int prot)
 		errno = EPERM;
 		return -1;
 	}
-	entry = &gdt->entries[gdt->entries_cnt];
-	/* base */
-	entry->base0 = base & 0xff;
-	entry->base1 = (base & 0xff00) >> 8;
-	entry->base2 = (base & 0xff0000) >> 16;
-	entry->base3 = (base & 0xff000000) >> 24;
 	/* limit */
 	if(size - 1 > GDT_LIMIT_MAX)
 	{
 		limit = (size & 0xfff) == 0
-			? (size >> 12)
-			: (((size | 0xfff) + 1) >> 12);
-		limit--;
+			? (size >> 12) - 1
+			: (((size | 0xfff) + 1) >> 12) - 1;
 		flags |= GDT_FLAG_PAGE_GRANULARITY;
 	}
 	else
 		limit = size - 1;
-	entry->limit0 = limit & 0xff;
-	entry->limit1 = (limit & 0xff00) >> 8;
-	entry->limit2 = (limit & 0xf0000) >> 16;
 	/* access */
 	if(prot == (PROT_READ | PROT_EXEC))
 		/* code segment */
-		access |= GDT_ACCESS_RW | GDT_ACCESS_X;
+		access |= GDT_ACCESS_PROT_RW | GDT_ACCESS_PROT_X;
 	else if(prot == (PROT_READ | PROT_WRITE))
 		/* data segment (read/write) */
-		access |= GDT_ACCESS_RW;
+		access |= GDT_ACCESS_PROT_RW;
 	else if(prot == PROT_READ)
 		/* data segment (read-only) */
 		access |= GDT_ACCESS_SET;
-	entry->access = access;
-	/* flags */
-	entry->flags = flags;
-	gdt->entries_cnt++;
-	return 0;
+	return _gdt_append_entry(gdt, base, limit, access, flags);
+}
+
+
+/* gdt_append_system */
+static int _append_system_ldt(GDT * gdt, void * base, size_t size);
+static int _append_system_tss(GDT * gdt, void * base, size_t size);
+
+int gdt_append_system(GDT * gdt, void * base, size_t size, unsigned int type)
+{
+	switch(type)
+	{
+		case GDT_SYSTEM_TYPE_LDT:
+			return _append_system_ldt(gdt, base, size);
+		case GDT_SYSTEM_TYPE_TSS:
+			return _append_system_tss(gdt, base, size);
+		default:
+			errno = ENOSYS;
+			return -1;
+	}
+}
+
+static int _append_system_ldt(GDT * gdt, void * base, size_t size)
+{
+	uint32_t access = GDT_ACCESS_PRESENT | GDT_SYSTEM_TYPE_LDT;
+	uint8_t flags = GDT_FLAG_PROTECTED_MODE;
+
+	if(size != sizeof(LDT))
+	{
+		errno = ERANGE;
+		return -1;
+	}
+	return _gdt_append_entry(gdt, (vaddr_t)base, size - 1, access, flags);
+}
+
+static int _append_system_tss(GDT * gdt, void * base, size_t size)
+{
+	uint32_t access = GDT_ACCESS_PRESENT | GDT_SYSTEM_TYPE_TSS;
+	uint8_t flags = GDT_FLAG_PROTECTED_MODE;
+
+	if(size != sizeof(TSS))
+	{
+		errno = ERANGE;
+		return -1;
+	}
+	return _gdt_append_entry(gdt, (vaddr_t)base, size - 1, access, flags);
 }
 
 
@@ -163,4 +220,32 @@ void gdt_apply(GDT * gdt)
 {
 	__arch_setgdt(gdt->entries, gdt->entries_cnt);
 }
+
+
+/* private */
+/* gdt_append_entry */
+static int _gdt_append_entry(GDT * gdt, vaddr_t base, uint32_t limit,
+		uint8_t access, uint8_t flags)
+{
+	GDTEntry * entry;
+
+	/* check for errors */
+	if(gdt->entries_cnt >= sizeof(gdt->entries) / sizeof(*gdt->entries))
+	{
+		errno = ENOMEM;
+		return -1;
+	}
+	entry = &gdt->entries[gdt->entries_cnt];
+	entry->base0 = base & 0xff;
+	entry->base1 = (base & 0xff00) >> 8;
+	entry->base2 = (base & 0xff0000) >> 16;
+	entry->base3 = (base & 0xff000000) >> 24;
+	entry->limit0 = limit & 0xff;
+	entry->limit1 = (limit & 0xff00) >> 8;
+	entry->limit2 = (limit & 0xf0000) >> 16;
+	entry->access = access;
+	entry->flags = flags;
+	gdt->entries_cnt++;
+	return 0;
+}
 #endif
diff --git a/src/loader/multiboot.c b/src/loader/multiboot.c
index 44ba76b..51225ea 100644
--- a/src/loader/multiboot.c
+++ b/src/loader/multiboot.c
@@ -1,5 +1,5 @@
 /* $Id$ */
-/* Copyright (c) 2018-2020 Pierre Pronchery <khorben@defora.org> */
+/* Copyright (c) 2018-2025 Pierre Pronchery <khorben@defora.org> */
 /* This file is part of DeforaOS uKernel */
 
 
@@ -87,7 +87,7 @@ int multiboot(const ukMultibootInfo * mi)
 
 	/* setup the GDT */
 	if(gdt_init_table((const GDTTable *)&_gdt_4gb,
-				sizeof(_gdt_4gb) / sizeof(*_gdt_4gb)) != 0)
+				sizeof(_gdt_4gb) / sizeof(*_gdt_4gb), 1) != 0)
 	{
 		puts("Could not setup the GDT");
 		return 4;
diff --git a/tests/gdt.c b/tests/gdt.c
index 36bc254..d5e38e8 100644
--- a/tests/gdt.c
+++ b/tests/gdt.c
@@ -12,6 +12,11 @@
 
 
 #if defined(__amd64__) || defined(__i386__)
+/* variables */
+static TSS tss;
+
+
+/* functions */
 /* __arch_setgdt */
 void __arch_setgdt(GDTEntry const * entries, size_t count)
 {
@@ -51,6 +56,7 @@ int main(int argc, char * argv[])
 	gdt = gdt_init();
 	gdt_append(gdt, 0x00000000, 0xffffffff, PROT_READ | PROT_EXEC);
 	gdt_append(gdt, 0x00000000, 0xffffffff, PROT_READ | PROT_WRITE);
+	gdt_append_system(gdt, &tss, sizeof(tss), GDT_SYSTEM_TYPE_TSS);
 	gdt_apply(gdt);
 
 	/* 4 MB code + 4 MB data (read-write) + 4 MB data (read-only) */
@@ -59,6 +65,7 @@ int main(int argc, char * argv[])
 	gdt_append(gdt, 0x00400000, 0x00400000, PROT_READ | PROT_EXEC);
 	gdt_append(gdt, 0x00800000, 0x00400000, PROT_READ | PROT_WRITE);
 	gdt_append(gdt, 0x00c00000, 0x00400000, PROT_READ);
+	gdt_append_system(gdt, &tss, sizeof(tss), GDT_SYSTEM_TYPE_TSS);
 	gdt_apply(gdt);
 
 #endif