AAccumulator
This directive may be used to display and/or alter the contents of the simulated accumulator. A space or comma follow- ing the A will display in binary, the contents of the simulated accumulator. This or the A may be followed either by a new value to be entered, or by a carriage return to end the directive.
CCarry/Link
This directive may be used to display and/or alter the contents of the simulated Carry/Link bit. The use of this direct- ive is the same as for A.
Xn Index
This directive may be used to display and/or alter the contents of anyone or pair of the simulated index registers. If a space or comma follows the X, all 16 index registers are displayed (in decimal). Otherwise, if the (decimal) number n is followed by a space, index register n may be displayed and/or altered as in A. If the number n is followed by a comma, slash, or period, index pair number n may be displayed (in decimal) and/or altered as a unit. (Index registers 2n and 2n + 1 are handled together as a single
SStack pointer
This directive may be used to display and/or alter the contents of the subroutine stack pointer. The current loca- tion counter is the one pointed to by this pointer. This pointer is incremented by JMS instructions and decremented by BBl instructions.
l location Counter
This directive may be used to display and/or alter the contents of the current location counter. Note that altering the value of the stack pointer will cause a different register to be current location counter.
EExamine Everything
This directive combines the display functions of the C, A, S, l, R, and X directives. All four program counters in the stack are displayed. No modification is possible.
RRAM/ROM selection
This directive may be used to display and/or modify the simulated memory chip/location seleetion. A space or comma after the R types out an
BBreakpoint
This directive may be used to display and/or modify the contents of the breakpoint register. The simulated execution will always be interrupted before processing the instruction pointed to by the breakpoint. If the breakpoint points to the second byte of a
WWhen
This directive may be used to display and/or alter the contents of the simulated sync cycle counter. This is a
TTrace
This directive causes the simulation program to begin simulated execution of the test program, beginning at the address in the current location counter. If instruction execution simulation is interrupted by a breakpoint, the keyboard BREAK key, or an illegal instruction, the T directive will cause the program to resume where it left off, just as if the program was never interrupted, except insofar as program parameters or registers were modified while interrupted. The basic format of the trace listing is
pppp:iiiiiiii c aaaa rr
where pppp is the decimal location counter; iiiiiiii is the binary representation of the (first byte of the) instruction being simulated; c is the resultant carry/I ink bit; aaaa is the resultant accumulator value; and rr is the resultant (decimal) index or index pair used in the instruction. (value, not index number) Any or all of the last three numbers may be omitted on instructions which do not reference their respective registers.
N
This directive is identical to the T directive, except that execution proceeds without tracing.
o Options
This directive may be used to display and/or alter the current option status bits. This is a
1Input, Output, and CPU test instructions are executed directly when this bit is on, instead of typing out on the teletype the port number and then typing or accepting the data.
10 No interrupt for subroutine stack overflow or underflow will occur when this bit is on.
1000 Unconditional jumps and subroutine jumps to ROM page 0 (chip 0) are executed directly instread of interpretively, permitting direct byte I/O during checkout.
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