!!! Doesn't work -- isem won't update it's instruction sequence...
!
! Program to store values hand entered into r10 in
! successive memory locations, so long as r11 remains
! zero.  The program will begin executing the entered
! values once r11 goes non-zero.
! If you try to enter more than twenty words, you'd better
! think very carefully about what will happen!
! Michael Johnson, 2001.
!	This program is a "machine language loader"
!	which is provided so that students can experience
!	writing, loading and executing their own machine
!	code using ISEM.

	.text 0x2000
start:
	nop	! All of these will be replaced by entered machine code.
	nop	! You must make sure you use ISEM in STEP mode, and you
	nop	! must put the next machine code instruction you want to
	nop	! enter in r10 before this program steps to address "loop:"
	nop	! each time.
	nop	! Remember that you can edit the contents of r10 directly
	nop	! using the register display window.
	nop
	nop
	nop
	nop
	nop
	nop
	nop
	nop
	nop
	nop
	nop
	nop
	nop
	set start, %r12		! Start address for the entered program
	add %r0, %r0, %r13	! r13 will be the displacement from start
				! for the next machine code instruction
loop:
	st %r10, [%r12+%r13]	! Store the next machine code instruction
	add %r13, 4, %r13	! Advance the displacement
	cmp %r11, 0		! Is r11 still zero?
	beq loop		!    If yes, store another instruction
	nop
	ba start		!    Else, start executing the entered
	nop			!    instructions.


	ta 0			! This should never be executed.