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Merged
merged 2 commits into from
Aug 9, 2025
Merged

Development #58

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49ee11a
VesaBIOSExtension
assembler-0 Aug 9, 2025
e670d3b
VesaBIOSExtension
assembler-0 Aug 9, 2025
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35 changes: 35 additions & 0 deletions arch/x86_64/asm/pxs.asm
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Original file line number Diff line number Diff line change
Expand Up @@ -6,12 +6,47 @@ header_start:
; checksum = -(magic + arch + length)
dd -(0xE85250D6 + 0 + (header_end - header_start))

; Framebuffer tag - request specific graphics mode
align 8
framebuffer_tag_start:
dw 5 ; type = framebuffer
dw 0 ; flags
dd 24 ; size
dd 1024 ; width
dd 768 ; height
dd 32 ; depth (bits per pixel)
framebuffer_tag_end:

; VBE tag - request VBE info
align 8
vbe_tag_start:
dw 7 ; type = VBE
dw 0 ; flags
dd vbe_tag_end - vbe_tag_start ; size
vbe_tag_end:

; End tag - required
align 8
dw 0 ; type
dw 0 ; flags
dd 8 ; size
header_end:

;section .multiboot
;header_start:
; dd 0xE85250D6 ; Multiboot2 magic number
; dd 0 ; Architecture 0 (protected mode i386)
; dd header_end - header_start ; header length
; ; checksum = -(magic + arch + length)
; dd -(0xE85250D6 + 0 + (header_end - header_start))
;
; ; End tag - required
; dw 0 ; type
; dw 0 ; flags
; dd 8 ; size
;header_end:
; fallback

bits 32

section .text
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1 change: 0 additions & 1 deletion drivers/Keyboard.c
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Original file line number Diff line number Diff line change
@@ -1,6 +1,5 @@
#include "Keyboard.h"
#include "Io.h"
#include "Console.h"

#define KEYBOARD_DATA_PORT 0x60
#define KEYBOARD_STATUS_PORT 0x64
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7 changes: 2 additions & 5 deletions drivers/Pic.c
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Original file line number Diff line number Diff line change
Expand Up @@ -12,14 +12,13 @@

void PitInstall() {
uint16_t divisor = 1193180 / PIT_FREQUENCY_HZ;

outb(0x43, 0x36); // Command byte: channel 0, lobyte/hibyte, rate generator
outb(0x40, divisor & 0xFF); // Low byte
outb(0x40, (divisor >> 8) & 0xFF); // High byte
}



void PicInstall() {
uint8_t a1, a2;

Expand All @@ -38,8 +37,6 @@ void PicInstall() {
outb(PIC1_DATA, ICW4_8086);
outb(PIC2_DATA, ICW4_8086);

outb(PIC2_DATA, ICW4_8086);

// Mask all interrupts initially
outb(PIC1_DATA, 0xFF); // Mask all on master PIC
outb(PIC2_DATA, 0xFF); // Mask all on slave PIC
Expand All @@ -53,7 +50,7 @@ void PicInstall() {
// Read current mask, clear bit 0, write back
uint8_t pic1_mask = inb(PIC1_DATA);
outb(PIC1_DATA, pic1_mask & ~0x01); // Clear bit 0 (IRQ0)

// Initialize PIT after PIC
PitInstall();
}
200 changes: 178 additions & 22 deletions drivers/Serial.c
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Original file line number Diff line number Diff line change
@@ -1,47 +1,203 @@
#include "Serial.h"
#include "Io.h"

#define COM1 0x3f8 // COM1
// Serial port register offsets
#define SERIAL_DATA_REG 0 // Data register (DLAB=0)
#define SERIAL_IER_REG 1 // Interrupt Enable Register (DLAB=0)
#define SERIAL_DIVISOR_LOW 0 // Divisor low byte (DLAB=1)
#define SERIAL_DIVISOR_HIGH 1 // Divisor high byte (DLAB=1)
#define SERIAL_FIFO_REG 2 // FIFO Control Register
#define SERIAL_LCR_REG 3 // Line Control Register
#define SERIAL_MCR_REG 4 // Modem Control Register
#define SERIAL_LSR_REG 5 // Line Status Register
#define SERIAL_MSR_REG 6 // Modem Status Register

void SerialInit(void) {
outb(COM1 + 1, 0x00); // Disable all interrupts
outb(COM1 + 3, 0x80); // Enable DLAB (set baud rate divisor)
outb(COM1 + 0, 0x03); // Set divisor to 3 (lo byte) -> 38400 baud
outb(COM1 + 1, 0x00); // (hi byte)
outb(COM1 + 3, 0x03); // 8 bits, no parity, one stop bit
// FIFO: enable (bit0), clear RX (bit1), clear TX (bit2), trigger=14 bytes (bits 6-7=11)
outb(COM1 + 2, 0xC7);
// Modem Control: DTR | RTS | OUT2 (keeps IRQ line enabled at PIC; actual serial IRQs still disabled since IER=0)
outb(COM1 + 4, 0x0B);
// Line Control Register bits
#define SERIAL_LCR_DLAB 0x80 // Divisor Latch Access Bit
#define SERIAL_LCR_8BITS 0x03 // 8 data bits
#define SERIAL_LCR_1STOP 0x00 // 1 stop bit
#define SERIAL_LCR_NOPARITY 0x00 // No parity

// Line Status Register bits
#define SERIAL_LSR_DATA_READY 0x01 // Data available
#define SERIAL_LSR_TRANSMIT_EMPTY 0x20 // Transmit buffer empty
#define SERIAL_LSR_IDLE 0x40 // Transmitter idle

// FIFO Control Register bits
#define SERIAL_FIFO_ENABLE 0x01
#define SERIAL_FIFO_CLEAR_RX 0x02
#define SERIAL_FIFO_CLEAR_TX 0x04
#define SERIAL_FIFO_TRIGGER_14 0xC0

// Modem Control Register bits
#define SERIAL_MCR_DTR 0x01
#define SERIAL_MCR_RTS 0x02
#define SERIAL_MCR_OUT2 0x08

static uint16_t serial_port = COM1;
static int serial_initialized = 0;

int SerialInit(void) {
return SerialInitPort(COM1);
}

int SerialInitPort(uint16_t port) {
serial_port = port;

// Test if serial port exists by writing to scratch register
outb(port + 7, 0xAE);
if (inb(port + 7) != 0xAE) {
return -1; // Port doesn't exist
}

// Disable all interrupts
outb(port + SERIAL_IER_REG, 0x00);

// Enable DLAB to set baud rate
outb(port + SERIAL_LCR_REG, SERIAL_LCR_DLAB);

// Set divisor to 3 (38400 baud)
outb(port + SERIAL_DIVISOR_LOW, 0x03);
outb(port + SERIAL_DIVISOR_HIGH, 0x00);

// Configure: 8 bits, no parity, 1 stop bit
outb(port + SERIAL_LCR_REG, SERIAL_LCR_8BITS | SERIAL_LCR_NOPARITY | SERIAL_LCR_1STOP);

// Enable and configure FIFO
outb(port + SERIAL_FIFO_REG, SERIAL_FIFO_ENABLE | SERIAL_FIFO_CLEAR_RX |
SERIAL_FIFO_CLEAR_TX | SERIAL_FIFO_TRIGGER_14);

// Enable DTR, RTS, and OUT2
outb(port + SERIAL_MCR_REG, SERIAL_MCR_DTR | SERIAL_MCR_RTS | SERIAL_MCR_OUT2);

// Test serial chip (loopback test)
outb(port + SERIAL_MCR_REG, SERIAL_MCR_DTR | SERIAL_MCR_RTS | SERIAL_MCR_OUT2 | 0x10);
outb(port + SERIAL_DATA_REG, 0xAE);

if (inb(port + SERIAL_DATA_REG) != 0xAE) {
return -2; // Serial chip failed
}

// Restore normal operation
outb(port + SERIAL_MCR_REG, SERIAL_MCR_DTR | SERIAL_MCR_RTS | SERIAL_MCR_OUT2);

serial_initialized = 1;
return 0; // Success
}
int is_transmit_empty(void) {
return inb(COM1 + 5) & 0x20;

int SerialTransmitEmpty(void) {
if (!serial_initialized) return 0;
return inb(serial_port + SERIAL_LSR_REG) & SERIAL_LSR_TRANSMIT_EMPTY;
}

int SerialDataAvailable(void) {
if (!serial_initialized) return 0;
return inb(serial_port + SERIAL_LSR_REG) & SERIAL_LSR_DATA_READY;
}

void SerialWriteChar(const char a) {
int SerialWriteChar(const char a) {
if (!serial_initialized) return -1;

// Timeout counter to prevent infinite loops
int timeout = 65536;

// If newline, emit CR first, then LF
if (a == '\n') {
while ((inb(COM1 + 5) & 0x20) == 0) {}
outb(COM1, '\r');
while (!SerialTransmitEmpty() && --timeout > 0);
if (timeout <= 0) return -1;
outb(serial_port + SERIAL_DATA_REG, '\r');
timeout = 65536; // Reset timeout
}

while (!SerialTransmitEmpty() && --timeout > 0);
if (timeout <= 0) return -1;

outb(serial_port + SERIAL_DATA_REG, a);
return 0;
}

int SerialReadChar(void) {
if (!serial_initialized) return -1;

if (!SerialDataAvailable()) {
return -1; // No data available
}
while ((inb(COM1 + 5) & 0x20) == 0) {}
outb(COM1, a);

return inb(serial_port + SERIAL_DATA_REG);
}

void SerialWrite(const char* str) {
int SerialWrite(const char* str) {
if (!str || !serial_initialized) return -1;

for (int i = 0; str[i] != '\0'; i++) {
SerialWriteChar(str[i]);
if (SerialWriteChar(str[i]) < 0) {
return -1;
}
}
return 0;
}

void SerialWriteHex(uint64_t value) {
if (!serial_initialized) return;

const char hex[] = "0123456789ABCDEF";
char buffer[17];
buffer[16] = '\0';

for (int i = 15; i >= 0; i--) {
buffer[15-i] = hex[(value >> (i * 4)) & 0xF];
}

SerialWrite(buffer);
}

void SerialWriteDec(uint64_t value) {
if (!serial_initialized) return;

if (value == 0) {
SerialWriteChar('0');
return;
}

char buffer[21]; // Max digits for uint64_t
int pos = 0;

while (value > 0) {
buffer[pos++] = '0' + (value % 10);
value /= 10;
}

// Reverse the string
for (int i = pos - 1; i >= 0; i--) {
SerialWriteChar(buffer[i]);
}
}

// Read a line from serial (with basic line editing)
int SerialReadLine(char* buffer, int max_length) {
if (!buffer || !serial_initialized || max_length <= 0) return -1;

int pos = 0;
int c;

while (pos < max_length - 1) {
c = SerialReadChar();
if (c < 0) continue; // No data, keep waiting

if (c == '\r' || c == '\n') {
SerialWriteChar('\n'); // Echo newline
break;
} else if (c == '\b' || c == 0x7F) { // Backspace or DEL
if (pos > 0) {
pos--;
SerialWrite("\b \b"); // Erase character on terminal
}
} else if (c >= 32 && c < 127) { // Printable characters
buffer[pos++] = c;
SerialWriteChar(c); // Echo character
}
}

buffer[pos] = '\0';
return pos;
}
39 changes: 34 additions & 5 deletions drivers/Serial.h
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Original file line number Diff line number Diff line change
@@ -1,10 +1,39 @@
#ifndef VOIDFRAME_SERIAL_H
#define VOIDFRAME_SERIAL_H
#include "stdint.h"

void SerialInit(void);
void SerialWriteChar(char c);
void SerialWrite(const char* str);
#include <stdint.h>

#define COM1 0x3f8 // COM1
#define COM2 0x2f8 // COM2
#define COM3 0x3e8 // COM3
#define COM4 0x2e8 // COM4

// Serial port addresses
#define SERIAL_COM1 0x3F8
#define SERIAL_COM2 0x2F8
#define SERIAL_COM3 0x3E8
#define SERIAL_COM4 0x2E8

// Initialize serial port (defaults to COM1)
int SerialInit(void);

// Initialize specific serial port
int SerialInitPort(uint16_t port);

// Status functions
int SerialTransmitEmpty(void);
int SerialDataAvailable(void);

// Character I/O
int SerialWriteChar(const char c);
int SerialReadChar(void);

// String I/O
int SerialWrite(const char* str);
int SerialReadLine(char* buffer, int max_length);

// Number output
void SerialWriteHex(uint64_t value);
void SerialWriteDec(uint64_t value);

Comment on lines +35 to 38
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🛠️ Refactor suggestion

Return-type inconsistency hampers error handling

All other I/O functions now return int for status; SerialWriteHex / SerialWriteDec still return void, so callers cannot detect transmit time-outs or un-initialised port.

-void SerialWriteHex(uint64_t value);
-void SerialWriteDec(uint64_t value);
+int  SerialWriteHex(uint64_t value);
+int  SerialWriteDec(uint64_t value);

Propagate the return codes inside the implementations for uniform API.

📝 Committable suggestion

‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

Suggested change
// Number output
void SerialWriteHex(uint64_t value);
void SerialWriteDec(uint64_t value);
// Number output
int SerialWriteHex(uint64_t value);
int SerialWriteDec(uint64_t value);
🤖 Prompt for AI Agents 
In drivers/Serial.h at lines 30 to 33, change the return type of SerialWriteHex
and SerialWriteDec from void to int to match other I/O functions. Update their
implementations to return status codes indicating success or failure, such as
transmit time-outs or uninitialized port errors, so callers can handle errors
uniformly.

#endif // VOIDFRAME_SERIAL_H
#endif // VOIDFRAME_SERIAL_H
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