// callback for handling interrupt
void hook_intr(uc_engine *uc, uint32_t intno, void *user_data)
{
uint32_t r_ip;
uint8_t r_ah;
uc_reg_read(uc, UC_X86_REG_IP, &r_ip);
uc_reg_read(uc, UC_X86_REG_AH, &r_ah);
// only handle DOS interrupt
switch(intno) {
default:
printf(">>> 0x%x: interrupt: %x, function %x\n", r_ip, intno, r_ah);
break;
case 0x21:
int21(uc);
break;
case 0x20:
int20(uc);
break;
}
}
void dokernel()
{
/*placeholder for the shell*/
char file[12800];
/*some friendly startup messages*/
bios_printstr("\r\nBuild an Operating System from Scratch Project\r\n\0");
bios_printstr("Written by Michael Black, December, 2007\r\n\n\0");
bios_printstr("Starting the kernel\r\n\0");
/*make the process table*/
initialize_process_table();
bios_printstr("Process table is initialized\r\n\0");
/*install the ISR for interrupt 21*/
makeinterrupt21();
int21(1,"Interrupt 21 is installed\r\n\0");
int21(1,"Kernel set up is completed\r\n\0");
int21(1,"Loading the shell into memory\r\n\0");
/*start the shell*/
/*load it into file[]*/
int21(3,"SHELL\0",file);
/*load it to memory and schedule it to be executed*/
int21(6,file,12800,"SHELL\0");
/*install an ISR for the timer - this will call the scheduler*/
maketimerinterrupt();
int21(1,"Timer interrupt is installed\r\n\0");
int21(1,"\r\nThe shell is starting. The kernel will stay in the background.\r\n\n\0");
}
/*kill a process*/
void dokill(char* line)
{
/*make the system call*/
char* arg=getargument(line);
int21(9,arg[0]-0x30);
}
void executeprogram(char* buffer, int bytelength)
{
int21(8,buffer,bytelength);
}
void deletefile(char* name)
{
int21(5,name);
}
void writefile(char* name, char* buffer, int sectorlength)
{
int21(4,name,buffer,sectorlength);
}
void readfile(char* name, char* buffer)
{
int21(3,name,buffer);
}
void readstring(char* buffer)
{
int21(2,buffer);
}
void printstring(char* string)
{
int21(1,string);
}
void exit()
{
int21(7);
}
void executeprogrambackground(char* buffer, int bytelength)
{
int21(6,buffer,bytelength);
}
void ps()
{
int21(17);
}
