CPU IO ports, and basic serial driver

.vscode/settings.json

@@ -0,0 +1,5 @@
+{
+    "files.associations": {
+        "serial.h": "c"
+    }
+}

makefile

@@ -2,7 +2,7 @@ CC := gcc
 AS := nasm
 CFLAGS = -c -mno-sse -mno-sse2 -mno-red-zone -ffreestanding -m32 -nostdlib -O3 -fno-pie -fno-stack-protector -mno-mmx
 BL_ASFLAGS := -f bin
-SRCS := $(wildcard src/kernel/*.c)
+SRCS := $(wildcard src/kernel/*/*.c)
 OBJS := $(patsubst src/kernel/%.c, bin/kernel/%.o, $(SRCS))
 
 all: bootloader tools kernel
@@ -16,12 +16,15 @@ tools:
 bootloader:
 	$(AS) src/bootloader/main.s $(BL_ASFLAGS) -o bin/bootloader.bin
 
-kernel: $(OBJS)
+# kernel: $(OBJS)
+kernel:
 	nasm src/kernel/entry.s -o bin/kernel/entry.o -f elf32
+	sh c_build_helper.sh
 	# ld -T linker.ld bin/kernel/entry.o bin/kernel/*.o -melf_i386
 	ld -T linker.ld bin/kernel/*.o -melf_i386
-%.o: $(SRCS)
-	$(CC) $(CFLAGS) $< -o $@
+# %.o: $(SRCS)
+# 	mkdir -p bin/kernel/$(shell dirname $@)
+# 	$(CC) $(CFLAGS) $< -o $@
 
 init:
 	@mkdir mount

src/bootloader/main.s

@@ -779,6 +779,7 @@ k_info:
     .yres:              dw 25
     .framebuffer_ptr:   dd 0xb8000
     .loaded_modules:    dd 0
+    .loaded_module_c:   dd 0
 ;loaded_modules points to a struct array containing a ptr to the entry point of each pre-loaded module to be executed during startup
 ;module_struct:
     ;.entry_point: dd 0

src/kernel/arch_i386/interrupts.c

@@ -0,0 +1,5 @@
+#include "../shared/interrupts.h"
+
+void init_idt(){
+    
+}

src/kernel/arch_i386/memory.c

@@ -0,0 +1,20 @@
+#include <stdint.h>
+#include "../shared/memory.h"
+#include "../shared/kstdlib.h"
+uint8_t pm_map[0x20000];
+
+int pm_alloc(){
+    
+}
+int pm_init(kernel_info_t *kernel_info){
+    
+}
+void map(void *vaddr, void *paddr, uint32_t flags){
+    uint32_t pd_index = (uint32_t)vaddr >> 22;
+    uint32_t pt_index = (uint32_t)vaddr >> 12 & 0x3ff;
+    
+    uint32_t *pd = (uint32_t*)0xfffff000;
+    if(!pd[pd_index]){
+        pd[pd_index] = pm_alloc();
+    }
+}

src/kernel/drivers/cpuio.h

@@ -0,0 +1,22 @@
+#pragma once
+#include <stdint.h>
+
+inline void outb(uint16_t port, uint8_t data){
+    asm volatile ("outb %0, %1" :: "a"(data), "Nd"(port));
+}
+
+inline void outw(uint16_t port, uint16_t data){
+    asm volatile ("outw %0, %1" :: "a"(data), "Nd"(port));
+}
+
+inline uint8_t inb(uint16_t port){
+    uint8_t byte = 0;
+    asm volatile ("inb %1, %0" : "=a"(byte) : "Nd"(port));
+    return byte;
+}
+
+inline uint16_t inw(uint16_t port){
+    uint16_t word = 0;
+    asm volatile ("inw %1, %0" : "=a"(word) : "Nd"(port));
+    return word;
+}

src/kernel/drivers/serial.c

@@ -0,0 +1,65 @@
+#include "serial.h"
+#include "../shared/memory.h"
+#include "../shared/string.h"
+#include "cpuio.h"
+#include <stdarg.h>
+#include <stdint.h>
+// #include <string.h>
+
+uint16_t com_ports[8];
+uint8_t com_buffer[8][128];
+uint8_t com_buffer_index[8] = {0};
+
+void init_serial(){
+    bda_t *bda = (void*)0x400;
+    for(int i = 0; i < 4; i++){
+        com_ports[i] = bda->com_ports[i];
+    }
+}
+void serial_writeb(uint8_t port, uint8_t data){
+    if(com_ports[port] == 0){
+        com_buffer[port][com_buffer_index[port]++] = data;
+    }
+    outb(com_ports[port], data);
+}
+uint8_t serial_readb(uint8_t port){
+    if(com_ports[port] == 0){
+        return com_buffer[port][com_buffer_index[port]--];
+    }
+    return inb(com_ports[port]);
+}
+void serial_writereg(uint8_t port, uint8_t reg, uint8_t data){
+    if(com_ports[port] == 0 || reg > 8) return;
+    outb(com_ports[port] + reg, data);
+}
+uint8_t serial_readreg(uint8_t port, uint8_t reg){
+    if(com_ports[port] == 0 || reg > 8) return -1;
+    return inb(com_ports[port] + reg);
+}
+
+void debug_puts(char *string){
+    while(*string){
+        // serial_writeb(0, *(string++));
+        outb(com_ports[0], *string++);
+    }
+}
+
+void printf(char *string, ...){
+    va_list vars;
+    va_start(vars, string);
+    while(*string){
+        if(*string == '%'){
+            switch(*(string + 1)){
+                case 'd':
+                    string += 2;
+                    int32_t num = va_arg(vars, int32_t);
+                    char numb[12];
+                    itoa(num, numb, 10);
+                    debug_puts(numb);
+                    continue;
+            }
+        }
+        outb(com_ports[0], *string);
+        string++;
+    }
+}

src/kernel/drivers/serial.h

@@ -0,0 +1,9 @@
+#pragma once
+#include <stdint.h>
+void init_serial();
+void serial_writeb(uint8_t port, uint8_t data);
+void serial_writereg(uint8_t port, uint8_t reg, uint8_t data);
+uint8_t serial_readreg(uint8_t port, uint8_t reg);
+uint8_t serial_readb(uint8_t port);
+void debug_puts(char *string);
+void printf(char *string, ...);

src/kernel/kmain.c

@@ -1,5 +1,10 @@
 #include "shared/memory.h"
-extern void kmain(){
-    pm_init();
+#include "shared/string.h"
+#include "shared/kstdlib.h"
+#include "drivers/serial.h"
+
+extern void kmain(kernel_info_t *kernel_info){
+    init_serial();
+    pm_init(kernel_info);
     return;
 }

src/kernel/shared/interrupts.h

@@ -0,0 +1 @@
+void init_idt();

src/kernel/shared/kstdlib.h

@@ -0,0 +1,12 @@
+#include "memory.h"
+typedef struct kernel_info{
+    memory_map_entry *mmap_ptr;
+    uint16_t mmap_entry_count;
+    uint8_t padding;
+    uint8_t pixel_depth;
+    uint16_t monitor_x_resolution;
+    uint16_t monitor_y_resolution;
+    void *framebuffer;
+    void *loaded_modues;
+    uint32_t loaded_module_count;
+}__attribute__((packed)) kernel_info_t;

src/kernel/shared/memory.h

@@ -0,0 +1,64 @@
+#pragma once
+#include <stdint.h>
+
+#define PD_PRESENT  0x0001
+#define PD_USER_RW  0x0002
+#define PD_USER     0x0004
+#define PD_PWT      0x0008
+#define PD_PCD      0x0010
+#define PD_ACCESSED 0x0020
+#define PD_DIRTY    0x0040
+#define PD_PAGE_SZ  0x0080
+#define PD_GLOBAL   0x0100
+#define PD_PAT      0x1000
+#define PD_LINK_N   0x0200
+#define PD_LINK_L   0x0400
+#define PD_ALLOC    0x0800
+
+#define PT_PRESENT  0X0001
+#define PT_USER_RW  0x0002
+#define PT_USER     0x0004
+#define PT_PWT      0x0008
+#define PT_PCD      0x0010
+#define PT_ACCESSED 0x0020
+#define PT_DIRTY    0x0040
+#define PT_PAT      0x0080
+#define PT_GLOBAL   0x0100
+#define PT_LINK_N   0x0200
+#define PT_LINK_L   0x0400
+#define PT_ALLOC    0x0800
+
+#define BIOS_MMAP_USABLE 1
+#define BIOS_MMAP_RESERVED 2
+#define BIOS_MMAP_RECLAIM 3
+#define BIOS_MMAP_NVS 4
+#define BIOS_MMAP_BAD_MEMORY 5
+
+typedef struct BIOS_data{
+    uint16_t com_ports[4];
+    uint16_t lpt_ports[3];
+    uint16_t ebda_addr;
+    uint16_t hw_bitflags;
+    uint16_t kb_to_ebda;
+    uint16_t kbd_state;
+    char     kbd_buffer[32];
+    uint8_t display_mode;
+    uint16_t columns_text;
+    uint16_t base_video_port;
+    uint16_t irq0_boot;
+    uint8_t hard_drives;
+    uint16_t kbd_buffer_start;
+    uint16_t kbd_buffer_end;
+    uint8_t kbd_led_state;
+}__attribute__((packed)) bda_t;
+
+typedef struct memory_map_entry{
+    uint64_t entry_base;
+    uint64_t entry_length;
+    uint32_t type;
+    uint32_t extended_bitflags;
+}__attribute__((packed))mmap_entry_t;
+
+void map(void *vaddr, void *paddr, uint32_t flags);
+void map_4mb(void *vaddr, void* paddr, uint32_t flags);
+int pm_init(kernel_info_t *kernel_info);

src/kernel/shared/string.h

@@ -0,0 +1,14 @@
+#pragma once
+#include <stdint.h>
+
+void itoa(int64_t data, char *res, uint8_t base);
+void strpad(char *string, char padding, uint32_t length);
+inline uint32_t strlen(char *str){
+    uint32_t c = 0;
+    while(*str){
+        str++;
+        c++;
+    }
+    return c;
+}
+void strcpy(char *src, char *dest);

src/kernel/system/string.c

@@ -0,0 +1,52 @@
+#include <stdint.h>
+#include "../shared/string.h"
+//res needs to allocate enough space for 12 chars minimum
+void itoa(int64_t data, char *res, uint8_t base){
+    char carr[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+    char negative = 0;
+    if(res == 0) return;
+    if(data < 0 && base == 10){
+        data *= -1;
+        negative = 1;
+    }
+    int ptr = 0;
+    char buffer[12] = {0};
+    // res[11] = 0;
+    if(data == 0){
+        res[0] = '0';
+        res[1] = 0;
+    }
+    uint32_t tmp = data;
+    while(tmp){
+        buffer[ptr++] = carr[tmp % base];
+        tmp /= base;
+    }
+    uint32_t rindex = 0;
+    res[ptr] = 0;
+    while(ptr > 0){
+        res[--ptr + negative] = buffer[rindex++];
+    }
+    res[0] += negative * '-';
+    return;
+}
+
+void strcpy(char *src, char *dest){
+    if(src == 0 || dest == 0){
+        return;
+    }
+    uint32_t len = strlen(src);
+    for(int i = 0; i < len; i++){
+        dest[i] = src[i];
+    }
+    dest[len] = 0;
+}
+
+void strpad(char *string, char padding, uint32_t length){
+    if(strlen(string) >= padding) return;
+    char tmp[length];
+    for(int i = 0; i < length - strlen(string); i++){
+        tmp[i] = padding;
+    }
+    strcpy(string, tmp + length - strlen(string));
+    strcpy(tmp, string);
+}