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5.2
Set Breakpoint
A single software breakpoint may be set at any editable location, by entering
B addr
The break is implemented by jamming a RST 38H instruction in that location,
cancelling any pre-existent breakpoint. Unlike (for example) MSDOS DEBUG,
breakpoints are persistent: they are not automatically cleared when the test-
program hits them. Rather, they are replaced in memory when the test program
is re-run, so they remain in force. To clear the breakpoint, enter "B" with no
arguments.
If a count value is entered after the address, the test program will not halt until
the breakpoint has been reached [count] times.
Caution: Breakpoints should only be set on the first op-code byte of a machine
instruction. Setting them elsewhere will have undefined consequences.
5.3
Display / Set Memory
The command format is
D addr [length]
If a length is given, the indicated number of bytes is rounded up to the next
multiple of 16, and the memory contents are displayed, 16 bytes to a lines, thus:
=D 500 27
0500 69 6E 20 49 6E 74 65 6C 2D 68 65 78 20 66 69 6C >in Intel-hex fil<
0510 65 3A 20 6C 61 73 74 20 62 61 64 20 6C 69 6E 65 >e: last bad line<
0520 3A 20 00 20 20 20 00 CD 36 02 DD 21 FB 10 3E E0 >: .
=
If only an address is entered, the current contents of that byte are displayed,
and a new value may be entered. If a blank line is entered, the value remains
unchanged, and the next byte is similarly displayed. Enter "Q" to exit from
this function.
=D 9500
9500 00 17
9501 00
9502 00 Q
21
..6..!..>.<
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