From e8c36b131ac12832bb1d5de0e3a710733fca88ac Mon Sep 17 00:00:00 2001
From: Nick Shipp <nick@shipp.ninja>
Date: Sun, 22 Apr 2018 18:32:50 -0400
Subject: Initial commit

---
 boot.s | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 76 insertions(+)
 create mode 100644 boot.s

(limited to 'boot.s')

diff --git a/boot.s b/boot.s
new file mode 100644
index 0000000..3f3457a
--- /dev/null
+++ b/boot.s
@@ -0,0 +1,76 @@
+bits 64
+
+section .text
+    org 0x0
+
+_start:
+    ; EFI System Table magic
+    mov rax, 0x5453595320494249
+    cmp rax, [rdx]
+
+    mov rdi, 0x1
+    jne fail			; Invalid magic
+
+;    mov r8, rax
+;    add r8, 0x1c
+;    mov word [rax+0x10], 0xfff
+;    mov qword [rax+0x12], r8
+;
+;    xor rcx, rcx
+;zero:
+;    mov qword [r8+rcx], 0x0
+;    add rcx, 0x8
+;    cmp rcx, 0xfff
+;    jle zero
+;
+;    lea r8, [rel int]
+;    mov word [rax+0x1c], r8w  ; offset_1
+;    shr r8, 16
+;    mov word [rax+0x1e], 0    ; selector
+;    mov byte [rax+0x20], 0    ; ist
+;    mov byte [rax+0x21], 0xff ; type_attr
+;    mov word [rax+0x22], r8w  ; offset_2
+;    shr r8, 16
+;    mov dword [rax+0x24], r8d ; offset_3
+;    mov dword [rax+0x28], 0   ; reserved, SBZ
+;
+;    cli
+;    lidt [rax+16]
+;    sti
+
+    ;int 0x0
+
+    push rbp
+    mov rbp, rsp
+    sub rsp, 0x30
+
+    mov rbx, rdx
+
+hello:
+    mov rcx, qword [rdx+0x40]	; arg0=ConOut
+    lea rdx, [rel msg]		; arg1=msg
+    call qword [rcx+0x8]	; OutputString
+
+    mov rdi, 0x0		; EFI_SUCCESS
+
+fail: ; error in rdi
+    mov rax, rdi
+    mov rsp, rbp
+    pop rbp
+    retn
+
+msg: db __utf16__ 'Hello, World',0xd,0,0xa,0,0,0
+
+; int:
+;     lea rax, [rel end]
+;     mov rdx, qword [rax+8]
+; 
+;     mov rcx, qword [rdx+0x40]	; arg0=ConOut
+;     lea rdx, [rel err]		; arg1=err
+;     call qword [rcx+0x8]	; OutputString
+; 
+;     iretq
+
+align 0x20
+
+end:
-- 
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