Implemented the basis for syscalls

A software interrupt with vector 0x50 will cause a syscall to start executing.
The EAX register will hold the syscall_num.
Other registers and the stack can be used to hold further arguments.

CoreLib/Memory.cpp

@@ -16,16 +16,14 @@ void* memset (void* ptr, int value, size_t num)
 
 int memcmp( const void* ptr1, const void* ptr2, size_t num)
 {
-    const unsigned char * cs = (const unsigned char*) ptr1;
+    auto* cs = (const unsigned char*) ptr1;
-    const unsigned char * ct = (const unsigned char*) ptr2;
+    auto* ct = (const unsigned char*) ptr2;
 
 
     for (int i = 0 ; i < num ; i++, cs++, ct++ ){
-        if( *cs < *ct){
+        if( *cs != *ct)
-            return -1;
+            return *cs - *ct;
-        } else if( *cs > *ct){
+
-            return 1;
-        }
     }
 
     return 0;

kernel/acpi/acpi.cpp

@@ -1,5 +1,6 @@
 #include "acpi.h"
 RSDPDescriptor* ACPI::rsd_ptr;
+RSCPDescriptor20* ACPI::rsd2_ptr;
 RSDT* ACPI::rsd_table;
 
 
@@ -8,19 +9,34 @@ void ACPI::initialize(){
 
     // Find the Root System Description Pointer
     ACPI::rsd_ptr = FindRSD();
+    printf("RSD address: 0x%x\n", ACPI::rsd_ptr);
+    //printRSD(rsd_ptr);
 
-    // is it valid
+
-    int sum = 0;
+    if( rsd_ptr->Revision == 0 ){
-    for (int i =0; i < 20 ; i++) {
+        // Using veriosn 1.0 of the ACPI specifiction
-        sum += ((char*)rsd_ptr)[i];
+        int sum = rsd_ptr->Checksum;
+        for (int i =0; i < sizeof(RSDPDescriptor) ; i++) {
+            sum += ((char*)rsd_ptr)[i];
+        }
+
+        printf(" 0x%x sum\n", sum);
+        if(sum & 0xfff0)
+            printf("valid rsd!\n");
+        else
+            printf("invalid rsd\n");
+
+
+        //  Get the Root System Description Table NOTE: might need memory mapping
+        //RSDT* rootSystemDescriptionTable = (RSDT*) (rsd_ptr->RsdtAddress + 0xC0000000);
+    } else{
+        // parse it as of version2.0
+        ACPI::rsd2_ptr = (RSCPDescriptor20*)rsd_ptr;
     }
 
-    printf(" 0x%x sum\n", sum);
-    return;
 
-    //  Get the Root System Description Table
-    RSDT* rootSystemDescriptionTable =  getRSDT((RSDPDescriptor *) rsd_ptr);
 
+/*
     auto tableHeader = &rootSystemDescriptionTable->h;
 
     // do checksum
@@ -31,5 +47,5 @@ void ACPI::initialize(){
     }
 
     if( sum != 0)
-        printf("Table invalid!");
+        printf("Table invalid!");*/
 }

kernel/acpi/acpi.h

@@ -7,7 +7,8 @@ class ACPI {
         // In the future ACPI might start
         // doing more systems initialization
 
+    static RSDPDescriptor* rsd_ptr;
+    static RSCPDescriptor20* rsd2_ptr;
+    static RSDT* rsd_table;
     private:
-       static RSDPDescriptor* rsd_ptr;
-       static RSDT* rsd_table;
 };

kernel/acpi/rsdp.cpp

@@ -1,5 +1,6 @@
 #include "rsdp.h"
 #include "../memory/VirtualMemoryManager.h"
+#include "../../CoreLib/Memory.h"
 
 
 void printRSD(RSDPDescriptor* rsd){
@@ -16,7 +17,6 @@ void printRSD(RSDPDescriptor* rsd){
     kterm_put('\n');
 
     printf("Revision: %d\n", rsd->Revision);
-    printf("RSDT Address: 0x%x\n", rsd->RsdtAddress );
 }
 
 RSDPDescriptor* FindRSD(){
@@ -31,10 +31,3 @@ RSDPDescriptor* FindRSD(){
     }
     return (RSDPDescriptor*) memory_byte;
 }
-
-
-RSDT* getRSDT(RSDPDescriptor* rsd){
-    printf("rsdt Address: 0x%x\n", rsd->RsdtAddress);
-    return (RSDT*)rsd->RsdtAddress ;
-
-}

kernel/acpi/rsdp.h

@@ -3,13 +3,6 @@
 #include <CoreLib/Memory.h>
 #include <stdint-gcc.h>
 
-struct RSDPDescriptor {
-    char signature[8];
-    uint8_t Checksum ;
-    char OEMID [6];
-    uint8_t Revision;
-    uint32_t RsdtAddress;
-}__attribute__((packed));
 
 struct ACPISDTHeader{
     char Signature[4];
@@ -28,6 +21,24 @@ struct RSDT{
     struct ACPISDTHeader h;
     uint32_t PointerToSDT[]; // Length of array : (header.Length - sizeof(header))/ 4
 }__attribute__((packed));
+
+
+struct RSDPDescriptor {
+    char signature[8];
+    uint8_t Checksum ;
+    char OEMID [6];
+    uint8_t Revision;
+    RSDT* RsdtAddress;
+}__attribute__((packed));
+
+struct RSCPDescriptor20{
+   RSDPDescriptor base;
+   uint32_t Length;
+   uint64_t XsdtAddress;
+   uint8_t ExtendedChecksum;
+   uint8_t reserved[3];
+}__attribute__((packed));
+
 RSDPDescriptor* FindRSD();
 
 void printRSD(RSDPDescriptor* rsd);

kernel/interrupts/idt.cpp

@@ -3,6 +3,9 @@
 #include "../drivers/ps-2/keyboard.h"
 #include "../i386/processor.h"
 #include "../memory/VirtualMemoryManager.h"
+#include "../syscalls.h"
+
+
 IDT_entry idt_table[256];
 IDT_ptr idt_ptr;
 
@@ -18,7 +21,7 @@ void set_id_entry (uint8_t num , uint32_t base, uint16_t sel,  uint8_t flags){
 
 void irs_handler (registers* regs) {
      uint32_t FaultingAddress;
-        //printf("(IRS) Interrupt number: %d \r", regs.int_no);
+        printf("(IRS) Interrupt number: %d \n EAX: ", regs->int_no, regs->eax);
         switch (regs->int_no)
         {
         case 0:
@@ -259,6 +262,29 @@ void irs_handler (registers* regs) {
             printf("EBP: 0x%x\n", regs->ebp); 
         break;
 
+        case 50:
+            printf("SYSTEMCALL\n");
+            printf("EAX 0x%x\n", regs->eax);
+
+                switch (regs->eax) {
+                    case 0x0:
+                        printf("test!\n");
+                        break;
+                    case 0x5:
+                        sys_open();
+                        break;
+                    case 0x10:
+                        sys_read((FILE*)regs->ebx, (char*)regs->ecx);
+                        break;
+                    case 0x20:
+                        sys_write((FILE*)regs->ebx, (const char*)regs->ecx, regs->edx);
+                        break;
+                    case 0x666:
+                        sys_version();
+                        break;
+
+                };
+        break;
         default:
             // PANIC!!!
             break;
@@ -269,9 +295,6 @@ void irs_handler (registers* regs) {
 }
 
 void irq_handler (registers regs) {
-
-    
-
     switch (regs.int_no) {
     case 0:
             pit_tick++;
@@ -328,7 +351,7 @@ void irq_handler (registers regs) {
 }
 
 void initidt(){
-    // Initialise the IDT pointer
+    // Initialize the IDT pointer
     idt_ptr.length = sizeof(IDT_entry) * 255;
     idt_ptr.base = (uint32_t)&idt_table;
 
@@ -371,7 +394,7 @@ void initidt(){
     set_id_entry(30, (uint32_t) irs30 , 0x08, 0x8E);
     set_id_entry(31, (uint32_t) irs31 , 0x08, 0x8E);
 
-
+    set_id_entry(0x50, (uint32_t) irs50, 0x08, 0x8E);
     //print_serial("Remapping PIC\n");
     PIC_remap(0x20, 0x28);
 

kernel/interrupts/idt.h

@@ -70,6 +70,7 @@ extern "C" {
     extern void irs29 ();
     extern void irs30 ();
     extern void irs31 ();
+    extern void irs50();
 
 
 

kernel/irq_table.s

@@ -1,115 +1,32 @@
 .globl irq0
-irq0:
-	cli 
-	push $0
-	push $0
-	jmp irq_common
 
-.globl irq1
+.macro IRQ NAME, VECTOR
-irq1:
+    .globl irq\NAME
-	cli 
+    irq\NAME:
-	push $0
+        cli
-	push $1
+        push $0
-	jmp irq_common
+        push \VECTOR
+        jmp irq_common
+.endm
 
-.globl irq2
+IRQ 0 $0
-irq2:
+IRQ 1 $1
-	cli 
+IRQ 2 $2
-	push $0
+IRQ 3 $3
-	push $2
+IRQ 4 $4
-	jmp irq_common
+IRQ 5 $5
-
+IRQ 6 $6
-.globl irq3
+IRQ 7 $7
-irq3:
+IRQ 8 $8
-	cli 
+IRQ 9 $9
-	push $0
+IRQ 10 $10
-	push $3
+IRQ 11 $11
-	jmp irq_common
+IRQ 12 $12
-
+IRQ 13 $13
-.globl irq4
+IRQ 14 $14
-irq4:
+IRQ 15 $15
-	cli 
-	push $0
-	push $4
-	jmp irq_common
-
-.globl irq5
-irq5:
-	cli 
-	push $0
-	push $5
-	jmp irq_common
-
-.globl irq6
-irq6:
-	cli 
-	push $0
-	push $6
-	jmp irq_common
-
-.globl irq7
-irq7:
-	cli 
-	push $0
-	push $7
-	jmp irq_common
-
-.globl irq8
-irq8:
-	cli 
-	push $0
-	push $8
-	jmp irq_common
-
-.globl irq9
-irq9:
-	cli 
-	push $0
-	push $9
-	jmp irq_common
-
-.globl irq10
-irq10:
-	cli 
-	push $0
-	push $10
-	jmp irq_common
-
-.globl irq11
-irq11:
-	cli 
-	push $0
-	push $11
-	jmp irq_common
 
 
-.globl irq12
-irq12:
-	cli 
-	push $0
-	push $12
-	jmp irq_common
-
-.globl irq13
-irq13:
-	cli 
-	push $0
-	push $13
-	jmp irq_common
-
-.globl irq14
-irq14:
-	cli 
-	push $0
-	push $14
-	jmp irq_common
-
-.globl irq15
-irq15:
-	cli 
-	push $0
-	push $15
-	jmp irq_common
 
 irq_common:
 	pusha

kernel/irs_table.s

@@ -53,7 +53,7 @@ ISR_NOERRORCODE 28 $28
 ISR_NOERRORCODE 29 $29
 ISR_NOERRORCODE 30 $30
 ISR_NOERRORCODE 31 $31
-
+ISR_NOERRORCODE 50 $50
 
 irs_common:
 	pusha 				# Pushes edi,esi,ebp,esp,ebx,edx,ecx,eax
@@ -74,7 +74,7 @@ irs_common:
 
 	call irs_handler
 	
-	pop %eax
+	pop %eax        // pop stack pointer
 	pop %ebx		// reload ther orignal data segment descriptor
 	mov %bx, %ds
 	mov %bx, %es
@@ -82,6 +82,6 @@ irs_common:
 	mov %bx, %gs
 
 	popa
-	add  $12, %esp  # cleans push error and irs code
+	add  $8, %esp  # cleans push error and irs code
 
 	iret # pops 5 things at once: CS, EIP, EFLAGS, SS, and ESP

kernel/kernel.cpp

@@ -9,23 +9,37 @@
 #include "drivers/vga/VBE.h"
 #include "pci/pci.h"
 #include "drivers/pit/pit.h"
-#include "acpi/acpi.h"
 #include "i386/processor.h"
 #include "terminal/kterm.h"
 #include "interrupts/idt.h"
 #include "serial.h"
 #include "storage/vfs/vfs.h"
 #include "storage/filesystems/FAT/FAT.h"
-#include "../CoreLib/Memory.h"
+#include "acpi/acpi.h"
+#include "memory/VirtualMemoryManager.h"
 
 
+extern BootInfoBlock* BIB;
 extern "C"  void LoadGlobalDescriptorTable();
 extern "C" void jump_usermode();
-extern BootInfoBlock* BIB;
+
+void initBootDrive(){
+    printf("Boot device: 0x%x\n", BIB->bootDeviceID);
+    unsigned int part3 = BIB->bootDeviceID & 0xFF;
+    unsigned int part2 = (BIB->bootDeviceID & 0xFF00) >> 8;
+    unsigned int part1 = (BIB->bootDeviceID & 0xFF0000) >> 16;
+    unsigned int drive = (BIB->bootDeviceID & 0xFF000000) >> 24;
+    if (drive == 0x80 )
+        printf("booted from disk!\n");
+    if(drive == 0x00)
+        printf("booted from floppy disk\n");
+
+    printf("Part1: %d, Part2: %d, Part3: %d\n", part1, part2 , part3);
+    ATAPIO::Identify(ATAPIO_PORT::Primary, DEVICE_DRIVE::MASTER);
+}
 
 extern "C" void kernel ()
 {
-
     init_serial();
     kterm_init();
 
@@ -42,32 +56,21 @@ extern "C" void kernel ()
     initHeap();
     pit_initialise();
     ACPI::initialize();
-
     PCI::Scan();
     processor::initialize();
     processor::enable_protectedMode();
-    printf("Boot device: 0x%x\n", BIB->bootDeviceID);
+    initBootDrive();
-    unsigned int part3 = BIB->bootDeviceID & 0xFF;
-    unsigned int part2 = (BIB->bootDeviceID & 0xFF00) >> 8;
-    unsigned int part1 = (BIB->bootDeviceID & 0xFF0000) >> 16;
-    unsigned int drive = (BIB->bootDeviceID & 0xFF000000) >> 24;
-    if (drive == 0x80 )
-        printf("booted from disk!\n");
-    if(drive == 0x00)
-        printf("booted from floppy disk\n");
-
-    printf("Part1: %d, Part2: %d, Part3: %d\n", part1, part2 , part3);
-    ATAPIO::Identify(ATAPIO_PORT::Primary, DEVICE_DRIVE::MASTER);
-
     VirtualFileSystem::initialize();
 
-    printf("Lets open hello.txt\n");
-    auto fontFile = VirtualFileSystem::open("/HELLO   TXT", 0);
-    if(fontFile->flags == 0){
-        uint16_t* contents = (uint16_t*) malloc(sizeof(uint16_t) * 256);
-        fontFile->read(fontFile, contents, 512);
     
-       for(int i =0 ; i < fontFile->root->size; i++ ){
+
+#ifdef VFS_EXAMPLE
+    auto fontFile = VirtualFileSystem::open("/FONT    PSF", 0);
+    if(grubcfg->flags == 0){
+        uint16_t* contents = (uint16_t*) malloc(sizeof(uint16_t) * 256);
+        grubcfg->read(grubcfg, contents, 512);
+
+        for(int i =0 ; i < grubcfg->root->size; i++ ){
             kterm_put(contents[i] & 0x00ff);
             kterm_put(contents[i] >> 8);
         }
@@ -76,8 +79,7 @@ extern "C" void kernel ()
     }else{
         printf("Could not find file\n");
     }
-
+#endif
-
 
 #ifdef USERMODE_RELEASE
     // Lets jump into user mode

kernel/supervisorterminal/superVisorTerminal.cpp

@@ -6,6 +6,8 @@
 bool isRunning = true;
 extern "C" void startSuperVisorTerminal()
 {
+
+
     /*
     * Show a little banner for cuteness
     */
@@ -62,7 +64,8 @@ extern "C" void startSuperVisorTerminal()
             {
                 // Show version information 
                 printf("========= Version ========\n");
-                printf("Kernel v%d\n", 0);
+
+                asm volatile ("movl $0x666, %eax; int $0x50");
 
             }
             if(strncmp("CLEAR", command, characterCount) == 0)

kernel/syscalls.h

@@ -0,0 +1,52 @@
+//
+// Created by nigel on 26/02/23.
+//
+#pragma once
+
+
+#include "terminal/kterm.h"
+#include "storage/vfs/vfs_types.h"
+
+
+void sys_version (){
+    printf("KERNEL VERSION v0.4\n");
+}
+
+void sys_open(){
+
+}
+
+void sys_read(FILE* file, char* data){
+    file->read(file, data, 512);
+}
+
+void sys_write(FILE* path, const char* data, size_t size){
+
+}
+
+// NOTE: this should become our standard!
+void syscall_handler(int syscall_no ,  uint32_t* args... ){
+    switch(syscall_no){
+        case 0x0:
+            printf("test!\n");
+            break;
+        case 0x5:
+            // SYS_OPEN
+            // sys_open();
+            break;
+        case 0x10:
+            // SYS_READ
+            // sys_read((FILE*)args[1], (char*) args[2] );
+            break;
+        case 0x20:
+            // SYS_WRITE
+            //sys_write((FILE*)args[1], (const char*) args[2], (size_t)args[3]);
+            break;
+        case 0x666:
+            // SYS_VERSION
+            sys_version();
+            break;
+    }
+}
+
+