From 4e09bca9e34c226b6d7e34b4fa11248405fd988e Mon Sep 17 00:00:00 2001
From: Anton Kling <anton@kling.gg>
Date: Sun, 22 Oct 2023 19:50:38 +0200
Subject: Move everything into a new repo.

---
 cpu/io.s | 121 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 121 insertions(+)
 create mode 100644 cpu/io.s

(limited to 'cpu/io.s')

diff --git a/cpu/io.s b/cpu/io.s
new file mode 100644
index 0000000..fe370a5
--- /dev/null
+++ b/cpu/io.s
@@ -0,0 +1,121 @@
+.intel_syntax noprefix
+.global outsw
+.global outb
+.global inb
+.global rep_outsw
+.global rep_insw
+.global flush_tss
+.global load_idtr
+
+# ebx, esi, edi, ebp, and esp;
+outsw:
+        push ebp
+	mov ebp, esp
+	push esi
+	mov dx, [ebp + 4+4]
+	mov esi, [ebp + 8+4]
+	outsw
+	pop esi
+	mov esp, ebp
+	pop ebp
+	ret
+
+outb:
+	mov al, [esp + 8]
+	mov dx, [esp + 4]
+	out dx, al
+	ret
+
+inb:
+	mov dx, [esp + 4]
+	in  al, dx
+	ret
+
+rep_outsw:
+        push ebp
+	mov ebp, esp
+	push edi
+	mov ecx, [ebp + 4+4]      #ECX is counter for OUTSW
+	mov edx, [ebp + 8+4]      #Data port, in and out
+	mov edi, [ebp + 12+4]		#Memory area
+	rep outsw               #in to [RDI]
+	pop edi
+	mov esp, ebp
+	pop ebp
+	ret
+
+rep_insw:
+        push ebp
+	mov ebp, esp
+	push edi
+	mov ecx, [ebp + 4+4]      #ECX is counter for INSW
+	mov edx, [ebp + 8+4]      #Data port, in and out
+	mov edi, [ebp + 12+4]		#Memory area
+	rep insw                #in to [RDI]
+	pop edi
+	mov esp, ebp
+	pop ebp
+	ret
+
+flush_tss:
+	mov ax, 40
+	ltr ax
+	ret
+
+load_idtr:
+	mov edx, [esp + 4]
+	lidt [edx]
+	ret
+
+test_user_function:
+	mov eax, 0x00
+	int 0x80
+	mov ecx, 0x03
+	mov ebx, 0x04
+	mov eax, 0x02
+	int 0x80
+	mov ebx, eax
+	mov eax, 0x01
+	int 0x80
+loop:
+	jmp loop
+	ret
+
+.global spin_lock
+.global spin_unlock
+.extern locked
+
+spin_lock:
+	mov eax, 1
+	xchg eax, ebx
+	test eax, eax     
+	jnz spin_lock
+	ret
+
+spin_unlock:
+	xor eax, eax
+	xchg eax, ebx
+	ret
+
+
+.global jump_usermode
+jump_usermode:
+	mov ax, (4 * 8) | 3 # user data segment with RPL 3
+	mov ds, ax
+	mov es, ax
+	mov fs, ax
+	mov gs, ax # sysexit sets SS
+ 
+	# setup wrmsr inputs
+	xor edx, edx # not necessary; set to 0
+	mov eax, 0x100008 # SS=0x10+0x10=0x20, CS=0x8+0x10=0x18
+	mov ecx, 0x174 # MSR specifier: IA32_SYSENTER_CS
+	wrmsr # set sysexit segments
+ 
+	# setup sysexit inputs
+	mov edx, [esp + 4] # to be loaded into EIP
+	mov ecx, [esp + 8] # to be loaded into ESP
+	mov esp, ecx
+	mov ebp, ecx
+	sti
+	sysexit
-- 
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