diff --git a/rom/debug.asm b/rom/debug.asm
index 9a0b8b9..42d4eba 100644
--- a/rom/debug.asm
+++ b/rom/debug.asm
@@ -49,7 +49,9 @@ init:	push ds
 	shl ax, cl
 	; load ES for relocate
 	mov es, ax
-	; store interrupt vector
+	; store interrupt vectors
+	mov word [1*4], int3entry
+	mov word [1*4+2], es
 	mov word [3*4], int3entry
 	mov word [3*4+2], es
 	; load DS for relocate
@@ -187,12 +189,21 @@ loop:	; new line & show prompt
 
 runcmd:	cmp al, 'r'
 	je printregs
+	cmp al, 'g'
+	je go
+	cmp al, 't'
+	je step
 	; print a question mark
 	xor bx, bx
 	mov ax, 0x0e3F
 	int 0x10
 	ret
 
+go:	and word [reg_fl+1], 0xfe
+	jmp return
+
+step:	or word [reg_fl+1], 0x03
+
 return:	; restore stack pointer
 	mov ss, [reg_ss]
 	mov sp, [reg_sp]