Added very basic interactive shell.

include/shell.h

@@ -0,0 +1,8 @@
+#ifndef __SHELL_H
+#define __SHELL_H
+
+void run_shell();
+void key_pressed(unsigned char* character);
+void execmd();
+
+#endif

include/system.h

@@ -9,6 +9,7 @@ extern unsigned short *memsetw(unsigned short *dest, unsigned short val, int cou
 extern int strlen(const char *str);
 extern unsigned char inportb (unsigned short _port);
 extern void outportb (unsigned short _port, unsigned char _data);
+extern bool strcmp(char* str1, char* str2);
 /* ISRS.C */
 void isrs_install();
 /* This defines what the stack looks like after an ISR was running */

makefile

@@ -12,7 +12,8 @@ objects = obj/start.o \
 	      obj/isrs.o \
 	      obj/irq.o \
 	      obj/timer.o \
-	      obj/kb.o
+	      obj/kb.o \
+	      obj/shell.o
 
 run: kernel.iso
 	qemu-system-x86_64 -cdrom kernel.iso &
@@ -26,7 +27,7 @@ obj/%.o: src/%.asm
 	nasm $(ASPARAMS) -o $@ $<
 
 kernel.bin: linker.ld $(objects)
-	mkdir obj/bin
+	mkdir -p obj/bin
 	ld $(LDPARAMS) -T $< -o obj/bin/$@ $(objects)
 #https://www.linuxjournal.com/content/add-auto-incrementing-build-number-your-build-process
 #include buildnumber.mak

src/kb.c

@@ -1,4 +1,5 @@
 #include "../include/system.h"
+#include "../include/shell.h"
 //http://www.osdever.net/bkerndev/Docs/keyboard.htm
 /* KBDUS means US Keyboard Layout. This is a scancode table
 *  used to layout a standard US keyboard. I have left some
@@ -51,10 +52,15 @@ bool shift = false;
 void keyboard_handler(struct regs *r)
 {
     unsigned char scancode;
-
     /* Read from the keyboard's data buffer */
     scancode = inportb(0x60);
 
+	if(scancode == 0x1C)
+	{
+		execmd();
+		return;
+	}
+
     /* If the top bit of the byte we read from the keyboard is
     *  set, that means that a key has just been released */
     if (scancode & 0x80)
@@ -89,7 +95,8 @@ void keyboard_handler(struct regs *r)
 		{
 			letter = letter - 32;
 		}
-        putch(letter);
+        //putch(letter);
+		key_pressed(letter);
     }
 }
 

src/main.c

@@ -2,6 +2,7 @@
 #include "../include/gdt.h"
 #include "../include/idt.h"
 #include "../include/scrn.h"
+#include "../include/shell.h"
 
 unsigned char *memcpy(unsigned char *dest, const unsigned char *src, int count)
 {
@@ -44,6 +45,24 @@ int strlen(const char *str)
     return retval;
 }
 
+bool strcmp(char* str1, char* str2)
+{
+	int len1 = strlen(str1);
+	int len2 = strlen(str2);
+
+	if(len1 != len2)
+	{
+		puts("Lengths different!\n");
+		return false;
+	}
+	for(int i = len1; i >= 0; i--)
+	{
+		if(str1[i] != str2[i]) return false;
+	}
+
+	return true;
+}
+
 /* We will use this later on for reading from the I/O ports to get data
 *  from devices such as the keyboard. We are using what is called
 *  'inline assembly' in these routines to actually do the work */
@@ -87,6 +106,7 @@ void main()
 	kb_install();
 	puts("Keyboard installed.\n");
 	puts("SDOS version 0.0.0.1 initialized.\n");
+	run_shell();
 	//puts(&__BUILD_DATE);
 	//puts(&__BUILD_NUMBER);
 	//puts("Divide by zero check:\n");

src/shell.c

@@ -0,0 +1,39 @@
+#include "../include/shell.h"
+#include "../include/scrn.h"
+#include "../include/system.h"
+
+unsigned char* commandbuffer;
+
+void run_shell()
+{
+	puts("Starting interactive shell...\n");
+	commandbuffer[0] = '\0';
+	puts("#>");
+	for(;;);
+}
+
+void key_pressed(unsigned char* character)
+{
+	int len = strlen(commandbuffer);
+	commandbuffer[len] = character;
+	commandbuffer[len + 1] = '\0';
+	putch(character);
+}
+
+void execmd()
+{
+	if(strcmp(commandbuffer, "version"))
+	{
+		puts("\nInteractive Shell Version 0.0.0.1\n");
+	}
+	else if(strcmp(commandbuffer,"cls"))
+	{
+		cls();
+	}
+	else
+	{
+		puts("\nUnknown command\n");
+	}
+	puts("#>");
+	commandbuffer[0] = '\0';
+}