From 8a6d52e8d4ae94da6f348de7e897c364765aa281 Mon Sep 17 00:00:00 2001
From: Nathan Cannon <neviynhd@gmail.com>
Date: Sat, 28 Apr 2018 01:03:53 +0100
Subject: [PATCH] Simplified GDT installation.

---
 kernel/arch/i386/gdt.nim | 29 ++++++++++++++---------------
 kernel/arch/i386/irq.nim | 11 -----------
 2 files changed, 14 insertions(+), 26 deletions(-)
 delete mode 100644 kernel/arch/i386/irq.nim

diff --git a/kernel/arch/i386/gdt.nim b/kernel/arch/i386/gdt.nim
index 8a5dafe..9fbe04e 100644
--- a/kernel/arch/i386/gdt.nim
+++ b/kernel/arch/i386/gdt.nim
@@ -18,23 +18,14 @@ type
     entries: array[0..2, GDTEntry]
 
 const
-  gdtAddress: uint32 = 0x00000800
+  gdtAddress: uint32 = 0x800
   gdt = cast[ptr GDT](gdtAddress)
 
-{.push stackTrace:off.}
 proc gdtFlush(){.inline,asmNoStackFrame.} =
   asm """
-    cli
-    lgdtl [`0x00000800`]
-    movw $0x10, %ax
-    movw %ax, %ds
-    movw %ax, %es
-    movw %ax, %fs
-    movw %ax, %gs
-    ljmp $0x08, $next
-    next:
+    lgdt (0x800)
+    ret
   """
-{.pop.}
 
 proc gdtSetGate(num: int, base: uint16, limit: uint32, access: AccessByte, flags: Flags) =
   # Setup the descriptor base address
@@ -62,15 +53,23 @@ proc createFlags(granularity: bool, size: bool): Flags =
     result = result or 0b01000000'u8
 
 proc gdtInstall*() =
-  gdt.descriptor.limit = uint16(sizeof(GDTEntry) * gdt.entries.len) - 1;
+  gdt.descriptor.limit = uint16(sizeof(gdt.entries)) - 1
   gdt.descriptor.base = cast[uint32](gdt.entries.addr)
+
   # NULL descriptor
   gdtSetGate(0, 0, 0, 0, 0);
 
   # The second entry is our Code Segment
-  gdtSetGate(1, 0'u16, 0xFFFFFFFF'u32, createAccessByte(0, false, true), createFlags(true, true));
+  gdtSetGate(1, 0'u16, 0xFFFFFFFF'u32, 0x9A, createFlags(true, true));
 
   # The third entry is our Data Segment
-  gdtSetGate(2, 0'u16, 0xFFFFFFFF'u32, createAccessByte(0, false, true), createFlags(true, true));
+  gdtSetGate(2, 0'u16, 0xFFFFFFFF'u32, 0x92, createFlags(true, true));
+
+  #gdtSetGate(3, 0'u16, 0xFFFFFFFF'u32, 0xFA, createFlags(true, true));
+
+  #gdtSetGate(4, 0'u16, 0xFFFFFFFF'u32, 0xF2, createFlags(true, true));
+  serial.write("GDT Address:")
+  serial.write(gdt.descriptor.base)
+  serial.write("\L")
   serial.write("Flushing GDT.\L")
   gdtFlush()
diff --git a/kernel/arch/i386/irq.nim b/kernel/arch/i386/irq.nim
deleted file mode 100644
index f0a5bad..0000000
--- a/kernel/arch/i386/irq.nim
+++ /dev/null
@@ -1,11 +0,0 @@
-type
-  InterruptFrame = ptr object
-    ip: uint
-    cs: uint
-    flags: uint
-    sp: uint
-    ss: uint
-
-# http://clang.llvm.org/docs/AttributeReference.html#interrupt-avr
-proc interrupt_handler(frame: InterruptFrame) {.exportc, codegenDecl: "__attribute__((interrupt)) $# $#$#".} =
-  discard