Blarg balr blarrr

build.sh

@@ -11,7 +11,7 @@ case $yn in
 	echo Removing Old Build Files...;
 	echo ---------------------------;
 
-	sudo make clean;
+	make clean;
 	echo -----;
 	echo Done!;
 	echo -----;
@@ -26,7 +26,7 @@ echo ------------
 echo COMPILING OS
 echo ------------
 
-sudo make -s
+make -s
 
 echo ---------
 echo Finished!
@@ -38,7 +38,7 @@ case $yn in
 	echo -------------
 	echo STARTING QEMU
 	echo -------------
-	sudo qemu-system-i386 -fda build/main_floppy.img
+	qemu-system-i386 -fda build/main_floppy.img
 	echo --------
 	echo Finshed!
 	echo --------

src/bootloader/stage2/disk.c

@@ -0,0 +1,48 @@
+/*----------------*\
+|Nanite OS         |
+|Copyright (C) 2024|
+|Tyler McGurrin    |
+\*----------------*/
+#include "disk.h"
+#include "x86.h"
+#include "stdio.h"
+
+bool DISK_Initialize(DISK* disk, uint8_t driveNumber) {
+    uint8_t driveType;
+    uint16_t cylinders, sectors, heads;
+    
+    if (!x86_Disk_GetDriveParams(disk->id, &driveType, &cylinders, &sectors, &heads))
+        return false;
+
+    disk->id = driveNumber;
+    disk->cylinders = cylinders + 1;
+    disk->heads = heads + 1;
+    disk->sectors = sectors;
+
+    return true;
+}
+
+void DISK_LBA2CHS(DISK* disk, uint32_t lba, uint16_t* cylinderOut, uint16_t* sectorOut, uint16_t* headOut) {
+    // sector = (LBA % sectors per track + 1)
+    *sectorOut = lba % disk->sectors +1;
+
+    // cylinder = (LBA / sects per track / heads)
+    *cylinderOut = (lba / disk->sectors) / disk->heads;
+
+    // head = (LBA / sects per track % heads)
+    *headOut = (lba / disk->sectors) % disk->heads;
+}
+
+bool DISK_ReadSectors(DISK* disk, uint32_t lba, uint8_t sectors, void* dataOut) {
+    uint16_t cylinder, sector, head;
+
+    DISK_LBA2CHS(disk, lba, &cylinder, &sector, &head);
+
+    for (int i = 0; i < 3; i++) {
+        if (x86_Disk_Read(disk->id, cylinder, sector, head, sectors, dataOut))
+            return true;
+        x86_Disk_Reset(disk->id);
+    }
+
+    return false;
+}

src/bootloader/stage2/disk.h

@@ -0,0 +1,20 @@
+/*----------------*\
+|Nanite OS         |
+|Copyright (C) 2024|
+|Tyler McGurrin    |
+\*----------------*/
+#pragma once
+
+#include "stdint.h"
+#include <stdbool.h>
+
+typedef struct {
+    uint8_t id;
+    uint16_t cylinders;
+    uint16_t sectors;
+    uint16_t heads;
+} DISK;
+
+bool DISK_Initialize(DISK* disk, uint8_t driveNumber);
+bool DISK_ReadSectors(DISK* disk, uint32_t lba, uint8_t sectors, void* lowerDataOut);
+

src/bootloader/stage2/main.c

@@ -5,29 +5,53 @@
 \*----------------*/
 #include <stdint.h>
 #include "stdio.h"
-// #include "disk.h"
+#include "x86.h"
+#include "disk.h"
 // #include "fat.h"
 
-// void far* g_data = (void far*)0x00500200;
 #define LOGO "    _   _____    _   __________________\n   / | / /   |  / | / /  _/_  __/ ____/\n  /  |/ / /| | /  |/ // /  / / / __/   \n / /|  / ___ |/ /|  // /  / / / /___   \n\\/_/ |_/_/  |_/_/ |_/___/ /_/ /_____/   \n"
 #define VERSION "v0.0.1"
 
+void* g_data = (void*)0x20000;
+
+ void puts_realmode(const char* str) {
+    while (*str) {
+        x86_realmode_putc(*str);
+        ++str;
+    }
+ }
+
  void __attribute__((cdecl)) start(uint16_t bootDrive) {
+    // Clear screen and Print Startup logo
     clrscr();
     printf("%s", LOGO);
     printf("                               %s\n--------------------------------------\n", VERSION);
 
-    for(;;);
+    // Test Real Mode
+    printf("Testing Real Mode...");
+    puts_realmode(" ");
+    printf("Ok!\n");
+
+    // get drive params (Test for Disk driver)
+    printf("Getting Drive Params...");
+    uint8_t driveType;
+    uint16_t cyls, sects, heads;
+    x86_Disk_GetDriveParams(bootDrive, &driveType, &cyls, &sects, &heads);
+    printf("Done!\n");
+    printf("> Drive Type: %u\n> Cylinders: %u\n> Sectors: %u\n> Heads: %u\n", driveType, cyls, sects, heads);
+
+    // init disk
+    printf("Initializing Disk...");
+    DISK disk;
+    if (!DISK_Initialize(&disk, bootDrive)) {
+        printf("Failed!\nDisk Initialization Error\n");
+        goto end;
+    }
+    printf("Done!\n");
+    DISK_ReadSectors(&disk, 0, 1, g_data);
+    print_buffer("> Boot Sector Data: ", g_data, 512);
 
 //     printf("Initializing FAT Driver...");
-//     DISK disk;
-//     if (!DISK_Initialize(&disk, bootDrive)) {
-//         printf("Failed!\nDisk Initialization Error\n");
-//         goto end;
-//     }
-
-//     DISK_ReadSectors(&disk, 19, 1, g_data);
-
 //     if (!FAT_Initialize(&disk)) {
 //         printf("Failed!\nDisk Initialization Error\n");
 //         goto end;
@@ -62,8 +86,8 @@
 //     }
 //     FAT_Close(fd);
 
-// end:
+end:
-//     for (;;);
+    for (;;);
 }
 
 

src/bootloader/stage2/x86.asm

@@ -1,20 +1,24 @@
 %macro x86_EnterRealMode 0
     [bits 32]
-    jmp work 18h:.pmode16
+    jmp word 18h:.pmode16         ; 1 - jump to 16-bit protected mode segment
 
 .pmode16:
     [bits 16]
+    ; 2 - disable protected mode bit in cr0
     mov eax, cr0
     and al, ~1
     mov cr0, eax
 
+    ; 3 - jump to real mode
     jmp word 00h:.rmode
 
 .rmode:
+    ; 4 - setup segments
     mov ax, 0
     mov ds, ax
     mov ss, ax
 
+    ; 5 - enable interrupts
     sti
 
 %endmacro
@@ -41,6 +45,23 @@
 
 %endmacro
 
+; Convert linear ADDR to seg:offset addr
+; Args:
+;   1 - linear addr
+;   2 - (OUT) target seg (ex. ES)
+;   3 - target 32 bit reg to use (ex. EAX)
+;   4 - target lower 16 bit half of 3 (ex. AX)
+
+%macro LinearToSegOffset 4
+
+    mov %3, %1    ;linear addr to EAX
+    shr %3, 4
+    mov %2, %4
+    mov %3, %1    ;linear addr to EAX
+    and %3, 0xF
+
+%endmacro
+
 
 global x86_outb
 x86_outb:
@@ -58,6 +79,183 @@ x86_inb:
     in al, dx
     ret
 
+;
+; bool _cdecl x86_Disk_GetDriveParams(uint8_t drive,
+;                                     uint8_t* driveTypeOut,
+;                                     uint16_t* cylindersOut,
+;                                     uint16_t* sectorsOut,
+;                                     uint16_t* headsOut);
+;
+global x86_Disk_GetDriveParams
+x86_Disk_GetDriveParams:
+    [bits 32]
+
+    ; make new call frame
+    push ebp             ; save old call frame
+    mov ebp, esp         ; initialize new call frame
+
+    x86_EnterRealMode
+
+    [bits 16]
+
+    ; save regs
+    push es
+    push bx
+    push esi
+    push di
+
+    ; call int13h
+    mov dl, [bp + 8]    ; dl - disk drive
+    mov ah, 08h
+    mov di, 0           ; es:di - 0000:0000
+    mov es, di
+    stc
+    int 13h
+
+    ; out params
+    mov eax, 1
+    sbb eax, 0
+
+    ; drive type from bl
+    LinearToSegOffset [bp + 12], es, esi, si
+    mov [es:si], bl
+
+    ; cylinders
+    mov bl, ch          ; cylinders - lower bits in ch
+    mov bh, cl          ; cylinders - upper bits in cl (6-7)
+    shr bh, 6
+    inc bx
+
+    LinearToSegOffset [bp + 16], es, esi, si
+    mov [es:si], bx
+
+    ; sectors
+    xor ch, ch          ; sectors - lower 5 bits in cl
+    and cl, 3Fh
+    
+    LinearToSegOffset [bp + 20], es, esi, si
+    mov [es:si], cx
+
+    ; heads
+    mov cl, dh          ; heads - dh
+    inc cx
+
+    LinearToSegOffset [bp + 24], es, esi, si
+    mov [es:si], cx
+
+    ; restore regs
+    pop di
+    pop esi
+    pop bx
+    pop es
+
+    ; return
+
+    push eax
+
+    x86_EnterProtectedMode
+
+    [bits 32]
+
+    pop eax
+
+    ; restore old call frame
+    mov esp, ebp
+    pop ebp
+    ret
+
+global x86_Disk_Reset
+x86_Disk_Reset:
+
+    ; make new call frame
+    push ebp             ; save old call frame
+    mov ebp, esp          ; initialize new call frame
+
+    x86_EnterRealMode
+
+    mov ah, 0
+    mov dl, [bp + 8]    ; dl - drive
+    stc
+    int 13h
+
+    mov eax, 1
+    sbb eax, 0           ; 1 on success, 0 on fail   
+
+    push eax
+
+    x86_EnterProtectedMode
+
+    pop eax
+
+    ; restore old call frame
+    mov esp, ebp
+    pop ebp
+    ret
+
+;
+; bool _cdecl x86_Disk_Read(uint8_t drive,
+;                           uint16_t cylinder,
+;                           uint16_t sector,
+;                           uint16_t head,
+;                           uint8_t count,
+;                           void far * dataOut);
+;
+global x86_Disk_Read
+x86_Disk_Read:
+
+    ; make new call frame
+    push ebp             ; save old call frame
+    mov ebp, esp          ; initialize new call frame
+
+    x86_EnterRealMode
+
+    ; save modified regs
+    push ebx
+    push es
+
+    ; setup args
+    mov dl, [bp + 8]    ; dl - drive
+
+    mov ch, [bp + 12]    ; ch - cylinder (lower 8 bits)
+    mov cl, [bp + 13]    ; cl - cylinder to bits 6-7
+    shl cl, 6
+    
+    mov al, [bp + 16]    ; cl - sector to bits 0-5
+    and al, 3Fh
+    or cl, al
+
+    mov dh, [bp + 20]   ; dh - head
+
+    mov al, [bp + 24]   ; al - count
+
+    LinearToSegOffset [bp + 28], es, ebx, bx
+
+    ; call int13h
+    mov ah, 02h
+    stc
+    int 13h
+
+    ; set return value
+    mov eax, 1
+    sbb eax, 0           ; 1 on success, 0 on fail   
+
+    ; restore regs
+    pop es
+    pop ebx
+
+    push eax
+
+    x86_EnterProtectedMode
+
+    pop eax
+
+    ; restore old call frame
+    mov esp, ebp
+    pop ebp
+    ret
+
+
+; Testing Function
 global x86_realmode_putc
 x86_realmode_putc:
     ; setup stack frame
@@ -66,7 +264,7 @@ x86_realmode_putc:
 
     x86_EnterRealMode
 
-    mov al, [sp + 8]
+    mov al, [bp + 8]
     mov ah, 0xe
     int 10h
 

src/bootloader/stage2/x86.h

@@ -1,5 +1,23 @@
 #pragma once
 #include <stdint.h>
+#include <stdbool.h>
 
 void __attribute__((cdecl)) x86_outb(uint16_t port, uint8_t value);
 uint8_t __attribute__((cdecl)) x86_inb(uint16_t port);
+
+void __attribute__((cdecl)) x86_realmode_putc(char c);
+
+bool __attribute__((cdecl)) x86_Disk_GetDriveParams(uint8_t drive,
+                                    uint8_t* driveTypeOut,
+                                    uint16_t* cylindersOut,
+                                    uint16_t* sectorsOut,
+                                    uint16_t* headsOut);
+
+bool __attribute__((cdecl)) x86_Disk_Reset(uint8_t drive);
+
+bool __attribute__((cdecl)) x86_Disk_Read(uint8_t drive,
+                          uint16_t cylinder,
+                          uint16_t sector,
+                          uint16_t head,
+                          uint8_t count,
+                          void* lowerDataOut);

write.sh

@@ -2,7 +2,7 @@ echo ------------
 echo COMPILING OS
 echo ------------
 
-sudo make
+make
 
 echo ---------
 echo Finished!