From 0d49245a603688c9093db15df0146d00f71e0ce1 Mon Sep 17 00:00:00 2001
From: Eric-Paul Ickhorn <ericp.ickhorn@gmail.com>
Date: Sun, 23 Jun 2024 23:25:03 +0200
Subject: [PATCH] Delete GDT-related files

This commit deletes the gdt.asm for the i386 architecture as it was
quite buggy in that state. In a short while, the real GDT code which
works is going to be committed.
---
 i386/loader/src-asm/memory/gdt.asm | 223 -----------------------------
 1 file changed, 223 deletions(-)
 delete mode 100755 i386/loader/src-asm/memory/gdt.asm

diff --git a/i386/loader/src-asm/memory/gdt.asm b/i386/loader/src-asm/memory/gdt.asm
deleted file mode 100755
index 0ffd7c6..0000000
--- a/i386/loader/src-asm/memory/gdt.asm
+++ /dev/null
@@ -1,223 +0,0 @@
-
-GDT_MEMORY_AREA equ 0x20000
-GDT_ENTRIES_CAPACITY equ 8
-GDT_ENTRY_SIZE equ 8
-
-db "gdt_set_segment"
-; [Furthest from EBP]
-;   3.  Bool (Lowest Address)   Task State Segment (0) or Code/Data (1)
-;       Bool (Second-Lowest)    Executable (1) or Not (0)
-;       Bool (Second-Highest)   Stack (1) or Heap (0) Page
-;       Bool (Highest Address)  Readable AND Writeable (1) or only what's necessary (0)
-;   2.  U32                     Number of pages
-;   1.  Ptr32                   Base address 
-;   0.  U32                     Index of Segment (0 is not allowed)
-; [Nearest to EBP]
-gdt_set_segment:
-.prolog:
-    push dword esi
-    sub esp, 64
-    mov esi, esp
-
-    mov [esi + (64 - 8)], ebx
-    mov [esi + (64 - 12)], ecx
-    mov [esi + (64 - 16)], edx
-    mov [esi + (64 - 20)], edi
-
-.get_work_address:
-    mov eax, [ebp - 4]
-    shl eax, 3
-    add eax, GDT_MEMORY_AREA
-    mov [esi], eax
-
-.prepare_flags_and_access_byte:
-    ; Access Privilege
-    ; [Highest]
-    ;   7.   Present Bit (Is in RAM: 1, is swapped out: 0)
-    ;   5+6. Descriptor Privilege Level (Kernel: 00, User; 11)
-    ;   4.   Descriptor Type (0: System Segment, 1: Code or Data Segment)
-    ;   3.   Is Executable? (Yes: 1, No: 0)
-    ;   2.   Grows Up (Heap) / Grows Down (Stack: 0, Heap, 1)
-    ;   1.   Secondary Access Bit (whether Read or Write is possible
-    ;        even when it isn't strictly necessary for the segment type)
-    ;   0.   Dirty Bit (Was Accessed: 1, Still Clean: 0)
-    ; [Lowest]
-
-    xor al, al
-    or al, (1 << 7) ; Present-Bit
-
-    cmp [ebp - 16], byte 0
-    je .after_task_segment_bit_setter
-    or al, (1 << 4)
-.after_task_segment_bit_setter:
-
-    cmp [ebp - 15], byte 0
-    je .after_executable_bit_setter
-    or al, (1 << 3)
-.after_executable_bit_setter:
-
-    cmp [ebp - 14], byte 0
-    je .after_direction_bit_setter
-    or al, (1 << 2)
-.after_direction_bit_setter:
-
-    cmp [ebp - 13], byte 0
-    je .after_read_write_bit_setter
-    or al, (1 <<  1)
-.after_read_write_bit_setter:
-
-    ; Flags
-    ; [Highest]
-    ;   3.  Address and Size Granularity (Bytes: 0, Pages: 1)
-    ;   2.  16-Bit or 32-Bit selector (0: 16-Bit, 1: 32-Bit)
-    ;   1.  Long Mode / 64-Bit
-    ;   0.  Reserved, should be 0
-    ; [Lowest]
-    mov ah, (0b00001100 << 4)
-
-    ; OR the uppermost 4 bits of the Limit into the
-    ; appropriate position in the byte of the flags.
-    mov ecx, [ebp - 12]
-    shr ecx, 16
-    and ecx, 0b00001111
-    or ah, cl
-
-    ; Store the Access Byte and the Flags into the entry.
-    mov ebx, [esi]
-    mov [ebx + 5], al ; Access Byte
-    mov [ebx + 6], ah ; Flags + Limit
-
-    mov eax, [ebp - 8] ; Base Address
-    mov [ebx + 2], ax
-    shr eax, 16
-    mov [ebx + 3], al
-    mov [ebx + 7], ah
-
-    mov ax, [ebp - 12]
-    mov [ebx], ax
-
-.epilog:
-    mov ebx, [esi + (64 - 8)]
-    mov ecx, [esi + (64 - 12)]
-    mov edx, [esi + (64 - 16)]
-    mov edi, [esi + (64 - 20)]
-    
-    add esp, 64
-    pop dword esi
-    ret
-
-
-
-db "load_flat_gdt"
-; [Furthest from EBP]
-;   0.      4B Return address
-; [Nearest to EBP]
-load_flat_gdt:
-.prolog:
-    push dword esi
-    sub esp, 64
-    mov esi, esp
-
-    mov [esi + (64 - 8)], ebx
-    mov [esi + (64 - 12)], ecx
-    mov [esi + (64 - 16)], edx
-    mov [esi + (64 - 20)], edi
-    mov eax, [ebp - 4]
-
-    mov [esi + 20], eax
-
-.create_gdt:
-
-    push ebp
-    mov ebp, esp
-    push dword (GDT_MEMORY_AREA - 16)
-    push dword gdt_identifier_text
-    push dword 8
-    call mem_copy
-    mov esp, ebp
-    pop ebp
-
-    ; Code Segment
-    push ebp
-    mov ebp, esp
-    push dword 1
-    push dword 0
-    push dword 0xfffff
-    push byte 1
-    push byte 0
-    push byte 1
-    push byte 1
-    call gdt_set_segment
-    mov esp, ebp
-    pop ebp
-
-    ; Stack Segment
-    push ebp
-    mov ebp, esp
-    push dword 2
-    push dword LOWER_STACK_POINTER
-    push dword 0fxffff
-    push byte 1
-    push byte 1
-    push byte 0
-    push byte 1
-    call gdt_set_segment
-    mov esp, ebp
-    pop ebp
-
-    ; Data Segment
-    push ebp
-    mov ebp, esp
-    push dword 3
-    push dword 0
-    push dword 0xfffff
-    push byte 1
-    push byte 0
-    push byte 1
-    push byte 1
-    call gdt_set_segment
-    mov esp, ebp
-    pop ebp
-
-    ; Write the GDT Descriptor
-    cli
-    lgdt [.gdtr]
-
-    mov ax, (3 << 3)
-    mov ds, ax
-    mov es, ax
-    mov fs, ax
-    mov gs, ax
-    mov ax, (2 << 3)
-    mov ss, ax
-
-    ; mov eax, cr0
-    ; or eax, 1
-    ; mov cr0, eax
-
-    cli
-    jmp dword 1:.after_far_jump
-
-.after_far_jump:
-    mov eax, cr0
-    or eax, 1
-    mov cr0, eax
-
-    mov esi, [esi + 20]
-    jmp esi
-    
-    mov ebx, [esi + (64 - 8)]
-    mov ecx, [esi + (64 - 12)]
-    mov edx, [esi + (64 - 16)]
-    mov edi, [esi + (64 - 20)]
-
-
-align 16
-.gdtr:
-.gdtr.length:
-    dw 31
-.gdtr.address:
-    dd GDT_MEMORY_AREA
-
-gdt_identifier_text:
-    db "GDT !!!!"