boot monitor: introduce a 'reset' command that causes the cpu to

reset (triple fault).

diff --git a/boot/boot.c b/boot/boot.c
index c72838fc1f48b101550546cc98a042270572a4b2..f73ae45b6f66901ed6ff2741857615f2d5c043fb 100644 (file)
--- a/boot/boot.c
+++ b/boot/boot.c
@@ -715,12 +715,12 @@ static void initialize(void)
 /* Reserved names: */
 enum resnames {
        R_NULL, R_BOOT, R_CTTY, R_DELAY, R_ECHO, R_EXIT, R_HELP,
-       R_LS, R_MENU, R_OFF, R_SAVE, R_SET, R_TRAP, R_UNSET
+       R_LS, R_MENU, R_OFF, R_SAVE, R_SET, R_TRAP, R_UNSET, R_RESET
 };
 
 static char resnames[][6] = {
        "", "boot", "ctty", "delay", "echo", "exit", "help",
-       "ls", "menu", "off", "save", "set", "trap", "unset",
+       "ls", "menu", "off", "save", "set", "trap", "unset", "reset",
 };
 
 /* Using this for all null strings saves a lot of memory. */
@@ -731,7 +731,7 @@ static enum resnames reserved(const char *s)
 {
        enum resnames r;
 
-       for (r= R_BOOT; r <= R_UNSET; r++) {
+       for (r= R_BOOT; r <= R_RESET; r++) {
                if (strcmp(s, resnames[r]) == 0) return r;
        }
        return R_NULL;
@@ -1877,6 +1877,7 @@ static void execute(void)
                case R_EXIT:    exit(0);
                case R_OFF:     off();          ok= 1;  break;
                case R_CTTY:    ctty(nil);      ok= 1;  break;
+               case R_RESET:   reset();        ok= 1;  break;
                }
 
                /* Command to check bootparams: */
@@ -2029,6 +2030,9 @@ void main(int argc, char **argv)
        }
        exit(0);
 }
+
+reset() { }
+
 #endif /* UNIX */
 
 /*

diff --git a/boot/boothead.s b/boot/boothead.s
index f72777ff135d4667a7b3b92c64c31dee88953125..7fefb1ec396039a5c01826222528a08b738cd5d5 100644 (file)
--- a/boot/boothead.s
+++ b/boot/boothead.s
@@ -1454,6 +1454,11 @@ _scan_keyboard:
        outb    0x61
        ret
 
+.define        _reset
+_reset:
+       lidt    idt_zero
+       int     0x3
+
 .data
        .ascii  "(null)\0"      ! Just in case someone follows a null pointer
        .align  2
@@ -1461,6 +1466,8 @@ c60:      .data2  60              ! Constants for MUL and DIV
 c1024: .data2  1024
 c1080: .data2  1080
 c19663:        .data2  19663
+idt_zero:
+.data4 0,0
 
 ! Global descriptor tables.
        UNSET   = 0             ! Must be computed