Implemented diskWrite() function!\nWe finally have disk operations!! Get ready for the filetable :)

src/kernel/disk.c

@@ -5,6 +5,7 @@
 #define PIO_PORT 0x1f0
 #define READ_COMMAND 0x20
 #define WRITE_COMMAND 0x30
+#define CACHE_FLUSH 0xE7
 
 void diskRead(uint32_t lbaAddress, uint8_t sectorCount, char* dst) {
     outb(PIO_PORT + 6, ((lbaAddress >> 24) & 0x0f) | 0xe0); // 6 - Use LBA; 4 - Drive number; 3-0 - Highest lba address nibble
@@ -29,3 +30,29 @@ void diskRead(uint32_t lbaAddress, uint8_t sectorCount, char* dst) {
     }
 }
 
+void diskWrite(uint32_t lbaAddress, uint8_t sectorCount, char* src) {
+    outb(PIO_PORT + 6, ((lbaAddress >> 24) & 0x0f) | 0xe0); // 6 - Use LBA; 4 - Drive number; 3-0 - Highest lba address nibble
+    outb(PIO_PORT + 2, sectorCount); // Sector count register
+    outb(PIO_PORT + 3, (uint8_t)(lbaAddress)); // Lowest lba address byte
+    outb(PIO_PORT + 4, (uint8_t)(lbaAddress >> 8)); // Middle lba address byte
+    outb(PIO_PORT + 5, (uint8_t)(lbaAddress >> 16)); // High lba address byte
+    outb(PIO_PORT + 7, WRITE_COMMAND); // Command register
+    
+    uint16_t* address = (uint16_t*)src;
+
+    for (uint8_t i = sectorCount; i > 0; i--) {
+        while (inb(PIO_PORT + 7) & (1 << 7)); // Poll status register untill BSY bit is clear
+
+        for (size_t j = 0; j < 256; j++) {
+            outw(PIO_PORT, *address++); // Write 256 words (512 Bytes = 1 Sector)
+        }
+
+        for (uint8_t delay = 0; delay < 4; delay++) { // 400ns delay
+            inb(0x3f6); // Alternate status register
+        }
+    }
+    
+    outb(PIO_PORT + 7, CACHE_FLUSH); // Cache flush
+    while (inb(PIO_PORT + 7) & (1 << 7)); // Poll status register untill BSY bit is clear
+}
+

src/kernel/disk.h

@@ -6,6 +6,6 @@
 extern uint8_t driveNum;
 
 void diskRead(uint32_t lbaAddress, uint8_t sectorCount, char* dst);
-// TODO: void diskWrite(uint8_t sector, uint8_t sectorCount, uint8_t drive, const char* src);
+void diskWrite(uint32_t lbaAddress, uint8_t sectorCount, char* src);
 
 #endif

src/kernel/main.c

@@ -39,42 +39,67 @@ void main() {
             args = strchr(input, '\n');
         }
 
-        *args = '\0'; // Separate command from args
-        args++;
+        *args++ = '\0'; // Separate command from args
 
         if (strcmp(input, "clear") == 0) {
             clear(0x0f);
         } else if (strcmp(input, "disk") == 0) {
-            static char buf[512];
+            char buf[512] = { 0 };
             
             if (*args == '\0') {
-                print("test: ", 0x0f);
+                print("disk: ", 0x0f);
                 print("No arguments given\n", 0x0c);
-                print("Usage: test <sector>\n", 0x0f);
+                print("Usage: disk <r/w> <sector> [data]\n", 0x0f);
                 continue;
             }
 
-            // TODO: We only support reading right now
-            //char mode = *args++;
-            //if (mode != 'r' || mode != 'w') {
-            //    print("test: ", 0x0f);
-            //    print("Invalid access mode. Use r(ead) or w(rite)\n", 0x0c);
-            //    print("Usage: test <r/w> <sector> [data]\n", 0x0f);
-            //    continue;
-            //}
-
-            uint32_t sector = atoi(args);
-            print("Reading...\n", 0x0f);
-            diskRead(sector, 1, buf);
+            while (isSpace(*args)) { args++; } // Skip whitespace
+            char mode = *args++;
+            while (isSpace(*args)) { args++; }
             
-            print("Contents:\n", 0x0f);
-            for (size_t i = 0; i < 512; i++) {
-                if (buf[i] != '\0') {
-                    putc(buf[i], 0x0f);
+            if (mode == 'r') {
+                if (*args == '\0') {
+                    print("disk: ", 0x0f);
+                    print("Sector not specified\n", 0x0c);
+                    print("Usage: disk <r/w> <sector> [data]\n", 0x0f);
+                    continue;
                 }
-            }
 
-            putc('\n', 0x0f);
+                uint32_t sector = atoi(args);
+                print("Reading...\n", 0x0f);
+                diskRead(sector, 1, buf);
+                
+                print("Contents:\n", 0x0f);
+                for (size_t i = 0; i < 512; i++) {
+                    if (buf[i] != '\0') {
+                        putc(buf[i], 0x0f);
+                    }
+                }
+
+                putc('\n', 0x0f);
+            } else if (mode == 'w') {
+                char* data;
+                if ((data = strchr(args, ' ')) == NULL) {
+                    print("disk: ", 0x0f);
+                    print("No data given\n", 0x0c);
+                    print("Usage: disk <r/w> <sector> [data]\n", 0x0f);
+                    continue;
+                }
+
+                *data++ = '\0';
+                uint32_t sector = atoi(args);
+
+                while (isSpace(*args)) { args++; } // Skip whitespace
+
+                strcpy(buf, data);
+                print("Writing...\n", 0x0f);
+                diskWrite(sector, 1, buf);
+            } else { 
+                print("disk: ", 0x0f);
+                print("Invalid access mode. Use r(ead) or w(rite)\n", 0x0c);
+                print("Usage: disk <r/w> <sector> [data]\n", 0x0f);
+                continue;
+            }
         } else if (strcmp(input, "echo") == 0) {
             print(args, 0x0f);
         } else if (strcmp(input, "exit") == 0) {

src/kernel/string.c

@@ -30,6 +30,11 @@ uint32_t atoi(const char* str) {
     return res;
 }
 
+int isSpace(char c) {
+    if (c == ' ' || c == '\t' || c == '\n') return 1;
+    else return 0;
+}
+
 // Some implementations taken from https://en.wikibooks.org/wiki/C_Programming/String_manipulation
 char* strcat(char* str1, const char* str2) {
     char* s = str1;

src/kernel/string.h

@@ -6,6 +6,8 @@
 char* itoa(uint32_t val, uint8_t base);
 uint32_t atoi(const char* str);
 
+int isSpace(char c);
+
 char* strcat(char* str1, const char* str2);
 char* strchr(const char* str, char c);
 int strcmp(const char* str1, const char* str2);