From 059b5ba286b3fef4d01c3ced9cd829ace5dd6340 Mon Sep 17 00:00:00 2001
From: Xander <xander@biltopia.org>
Date: Fri, 14 Jul 2023 12:28:07 +0200
Subject: Task state segment structs

---
 kernel/tss.dats | 20 ++++++++++++++++++++
 kernel/tss.sats | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 68 insertions(+)
 create mode 100644 kernel/tss.dats
 create mode 100644 kernel/tss.sats

diff --git a/kernel/tss.dats b/kernel/tss.dats
new file mode 100644
index 0000000..e4569d6
--- /dev/null
+++ b/kernel/tss.dats
@@ -0,0 +1,20 @@
+#include "kernel/prelude/kernel_prelude.hats"
+
+#define ATS_DYNLOADFLAG 0
+
+staload "./tss.sats"
+
+staload UN = "prelude/SATS/unsafe.sats"
+
+var tss : tss_t // Task State Segment
+var stack1 : stack // Double fault stack
+
+implement tss_init() : void = let
+  extern praxi __assert{l:addr} (ptr: ptr (l)): vtakeout0 (tss_t@l)
+  prval (pf, fpf) = __assert (addr@(tss)) // takeout proof  UNSAFE:
+  val sp1 = @{a = ptr_add<uint8>(addr@(stack1),STACK_SIZE)} 
+in
+  tss.ist.IS1 := sp1;
+  let prval () = fpf(pf) in end
+end
+
diff --git a/kernel/tss.sats b/kernel/tss.sats
new file mode 100644
index 0000000..e5016a8
--- /dev/null
+++ b/kernel/tss.sats
@@ -0,0 +1,48 @@
+#define
+STACK_SIZE 4096
+
+// Stack pointer
+typedef sp_t = @{
+  (* low = uint32, // The higher 32 bits of stack pointer *)
+  (* high = uint32 /// The lower 32 bits of stack pointer *)
+  a = [l : addr] ptr l
+}
+
+// Interrupt Stack table
+typedef ist_t = @{
+  IS1 = sp_t, // Interrupt stack pointer 1
+  IS2 = sp_t, // Interrupt stack pointer 2
+  IS3 = sp_t, // Interrupt stack pointer 3
+  IS4 = sp_t, // Interrupt stack pointer 4
+  IS5 = sp_t, // Interrupt stack pointer 5
+  IS6 = sp_t, // Interrupt stack pointer 6
+  IS7 = sp_t // Interrupt stack pointer 7
+}
+
+// Privilege change stack table
+typedef rst_t = @{
+  RSP0 = sp_t, // Points to stack with privilege level 0
+  RSP1 = sp_t, // Points to stack with privilege level 1
+  RSP2 = sp_t // Points to stack with privilege level 2
+}
+
+// I/O Permission Bitmap
+typedef iopb_t = uint16
+
+//Task state segment
+typedef tss_t = @{
+  r1 = uint32 0, // Reserved space
+  rst = rst_t,  
+  r2 = uint32 0, // Reserved space
+  r3 = uint32 0, // Reserved space
+  ist = ist_t,
+  r4 = uint32 0, // Reserved space
+  r5 = uint32 0, // Reserved space
+  r6 = uint16 0, // Reserved space
+  iopb = iopb_t
+}
+
+typedef stack = @[uint8][STACK_SIZE]
+
+fun tss_init() : void
+
-- 
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