hazel/user/shell.c

#include "../lib/strcmp.h"

static const char test[] = "Hello\n";

int strlen(const char *str) {
    const char *s;
    for (s = str; *s; s++)
        ;

    return s - str;
}

void putc(const char c) {
    asm volatile (
	    "movl $1, %%eax\n\t"
	    "movl $1, %%edi\n\t"
	    "movl %0, %%esi\n\t"
	    "movl $1, %%edx\n\t"
	    "int $0x80"
	    : 
	    : "r"(&c)
	    : "%eax", "%edi", "%esi", "%edx"
	    );
}

void puts(const char *str) {
    asm volatile (
	    "movl $1, %%eax\n\t"
	    "movl $1, %%edi\n\t"
	    "movl %0, %%esi\n\t"
	    "movl %1, %%edx\n\t"
	    "int $0x80"
	    : 
	    : "r"(str), "r"(strlen(str))
	    : "%eax", "%edi", "%esi", "%edx"
	    );
}

void read(int fd, void *buf, int size) {
    asm volatile (
	    "movl $0, %%eax\n\t"
	    "int $0x80"
	    : 
	    : "D"(fd), "d"(size), "S"(buf)
	    : "eax"
	    );
}

void reboot() {
    asm volatile (
	    "movl $2, %%eax\n\t"
	    "int $0x80"
	    : 
	    : 
	    : "eax"
	    );
}

uint64_t uptime() {
    uint32_t low = 0;
    uint32_t high = 0;
    asm volatile (
	    "movl $3, %%eax\n\t"
	    "movl %0, %%esi\n\t"
	    "movl %1, %%edi\n\t"
	    "int $0x80"
	    : 
	    : "r" (&low), "r" (&high)
	    : "eax", "esi"
	    );

    return (uint64_t)low | ((uint64_t)high << 32);
}

extern char *buf;

void print_int(int num){
    if (num < 0)
    {
       putc('-');
       num = -num;
    }

    if (num > 9) print_int(num/10);

    putc(('0'+ (num%10)));
 }

void _start() {
    char buf1[256] = {0};
    //puts("Welcome to the Hazel user shell!\n");
    puts(test);
    while (1) {
	puts("$ ");
	read(0, buf1, 256);
        if (!strcmp(buf1, "SKIBIDI")) {
            puts("dop dop yes yes!\n");
        } else if (!strcmp(buf1, "REBOOT")) {
            reboot();
        } else if (!strcmp(buf1, "UPTIME")) {
            uint64_t ticks = uptime();
            print_int(ticks);
            puts("\n");
        }
        else {
            puts("unknown command!\n");
        }
    }
}