Font, README, & work on paging

README.md

@@ -42,10 +42,10 @@ qemu-system-x86_64 disk.img
 You'll obviously need Qemu installed.
 
 ### On real hardware
-This is ***not recommended***, and it has ***not been tested***, however you're welcome to give it a shot. In the directory of the .bin file, run:
+This is ***not recommended***, and it has ***not been tested***, however you're welcome to give it a shot. In the directory of the .img file, run:
 
 ```
-sudo dd if=SpecOS/scripts/disk.img of=/dev/sdN bs=4M status=progress
+sudo dd if=disk.img of=/dev/sdN bs=4M status=progress
 ```
 
 With /dev/sdN being the name of your USB. Then in your device's unique BIOS, change the boot order so it will boot from USB before your current OS, and restart with your now-formatted USB plugged in.
@@ -101,3 +101,9 @@ Some things that I gotta do, and some things that I have done, in SpecOS. Yeah,
 It's a road to running DOOM!
 
 Note that a lot of this is unrealistic and probably won't happen - it's a lot easier said that done. But my hopes are high (:
+
+## Special thanks
+You didn't *really* think that *I* could do this alone of all people, did you? I'm not a genius! Thank you so, so much to these people who have made my journey in operating system development so much easier!
+
+ - [Bananymous](https://github.com/Bananymous) is a super smart guy, who taught me a *ton*. He also wrote the amazing [Banan-OS](https://github.com/Bananymous/banan-os)!
+ - [Dcraftbg](https://github.com/Dcraftbg) has taught me a whole lot about paging and a few other topics. He also just managed to enter userspace on his [MinOS](https://github.com/Dcraftbg/MinOS), nice one :D

drivers/vga.c

@@ -52,12 +52,12 @@ void drawPix(int x, int y, int colour) {
 }
 
 void drawChar(int xOffset, int yOffset, int colour, char ch) {
-    int firstByteIdx = ch * 8;
+    int firstByteIdx = ch * 16;
     bool doDrawBuffer;
     int colourBuffer;
-    for (int by = 0; by < 8; by++) { 
+    for (int by = 0; by < 16; by++) { 
         for (int bi = 0; bi < 8; bi++) {
-            doDrawBuffer = (fontdata_8x8[firstByteIdx + by] >> (7 - bi)) & 1;
+            doDrawBuffer = (fontGlyphBuffer[firstByteIdx + by] >> (7 - bi)) & 1;
             if (doDrawBuffer)
                 colourBuffer = colour;
             else
@@ -75,7 +75,7 @@ void writeChar(char ch, int colour) {
 }
 
 void newline() {
-    kernel.chY += 10;
+    kernel.chY += 16;
     kernel.chX = 5;
 }
 

kernel.c

@@ -55,7 +55,7 @@ void initKernelData() {
 void _start() {
     initKernelData();
     init_serial();
-    initVGA(); 
+    initVGA();
     // Just send output to a serial port to test
     writestring("Trying to initialise GDT...\n");
     initGDT();
@@ -65,18 +65,18 @@ void _start() {
     writestring("\nStarting physical memory manager...");
     initPMM();
     // this is commented out cos paging doesn't work yet and it's still in progress.
-    //writestring("\nInitiating paging...");
-    //initPaging();
-    char buffer[10];
-    uint64_t tableSingle;
-    for (int i = 0; i < 5; i++) {
-        for (int y = 0; y < 10; y++)
-            buffer[y] = 0;
-        tableSingle = *(uint64_t*)&(kernel.GDT)[i];
-        uint64_to_hex_string((uint64_t)tableSingle, buffer);
-        writestring("\nGDT contents: 0x");
-        writestring(buffer);
-    }
+    /*writestring("\nInitiating paging...");
+    struct pmlEntry* pml4Address = initPaging(); 
+    printf("\nPages mapped, trying to reload cr3...");
+    // load a pointer to pml4 into cr3 and change the stack to point elsewhere
+    __asm__ volatile (
+//        "movq %0, %%rsp;"
+//        "movq %1, %%rbp;"
+        "movq %1, %%cr3"
+        : : "r" ((uint64_t) 0xfffffffffffff000),
+            "r" ((uint64_t) pml4Address)
+    );
+    printf("\nPaging successfully enabled!");*/
     test_userspace();
     for (;;);
 }

mem/include/paging.h

@@ -7,6 +7,22 @@
 #ifndef PAGING_H
 #define PAGING_H
 
-void initPaging();
+struct pmlEntry {
+    uint8_t isPresent : 1;
+    uint8_t isReadOrWrite : 1;
+    uint8_t isUserOrSupervisor : 1;
+    uint8_t pwt : 1;
+    uint8_t cacheDisable : 1;
+    uint8_t accessed : 1;
+    uint8_t avaliable : 1;
+    uint8_t rsvdOrPageSize : 1; // rsvd if normal pml entry, page size if it's a pdpt entry or page directory entry. doesn't really matter cos it's 0 either way.
+    uint8_t avaliable2 : 4;
+    uint64_t address : 40;
+    // think there should be reserved bits here? think again! assume M = 51.
+    uint16_t available3 : 11;
+    uint8_t executeDisable : 1;
+} __attribute__((packed));
+
+struct pmlEntry* initPaging();
 
 #endif

mem/paging.c

@@ -28,22 +28,6 @@
 // make it know what stuff is
 // this is one definition, cos pml 1->4 are all basically the same
 // it's just layers of page directories
-struct pmlEntry {
-    uint8_t isPresent : 1;
-    uint8_t isReadOrWrite : 1;
-    uint8_t isUserOrSupervisor : 1;
-    uint8_t pwt : 1;
-    uint8_t cacheDisable : 1;
-    uint8_t accessed : 1;
-    uint8_t avaliable : 1;
-    uint8_t rsvdOrPageSize : 1; // rsvd if normal pml entry, page size if it's a pdpt entry or page directory entry. doesn't really matter cos it's 0 either way.
-    uint8_t avaliable2 : 4;
-    uint64_t address : 40;
-    // think there should be reserved bits here? think again! assume M = 51.
-    uint16_t available3 : 11;
-    uint8_t executeDisable : 1;
-} __attribute__((packed));
-
 // set up the structure
 struct pmlEntry pml4[512] __attribute__((aligned(4096)));
 
@@ -117,7 +101,7 @@ void mapConsecutivePages(struct pmlEntry pml4[], uint64_t startingPhysAddr, uint
     }
 }
 
-void initPaging() {
+struct pmlEntry* initPaging() {
     /* page entries will be defined later when filling pml1
      * and so will the pdpt when loading it into cr3
      * fill up pml1 with mappings
@@ -133,15 +117,8 @@ void initPaging() {
     for (uint64_t i = startingPageFrame; i < endPageFrame; i++) { 
         mapPage(pml4, (uint64_t) kmalloc(), i, true);
     }
-    printf("\nPages mapped, trying to reload cr3...");
-    // load a pointer to pml4 into cr3 and change the stack to point elsewhere
-    __asm__ volatile (
-        "movq %0, %%cr3;"
-        "movq %1, %%rsp"
-        : : "r" ((uint64_t) pml4 + kernel.hhdm),
-            "r" ((uint64_t) 0xfffffffffffff000)
-    );
-    printf("\nPaging successfully enabled!");
+    // return some stuff so the entry point function of the kernel can reload cr3
+    return pml4 + kernel.hhdm;
     // no need to enable paging, limine already enables it :D
 }