Mostek z80 - B-Breakpoint Command; Description of B Command

3.14 B-BREAKPOINT CCMo1AND
FORMATS:
,B lCR)
,~ ~CR)
,B a,H{CR)
,8 a,C{CR)
,S C,A{CR)
,B H,O{CR)
,8 t,u,T{CR)
,!! x,C,T{CR)
3.15 DESCRIPTION, B COMMAND
< Tabulate breakpoints
< Set software breakpoint
< Set hardware breakpoint
< Clear breakpoint
< Clear All breakpoints
< Specify History Options
< Set timeout breakpoint
< Clear timeout breakpoint
(l)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
3-11
Format (I) of the 8 commacrl is used to tabulate the hardware, software, and
timer breakpoints. There are no operands associated with this fonnat acrl it
may be used at any time.
Format (2) is used to Set a software breakpoint. Up to eight software
breakpoints may be set. The address of the breakpoint is stored in a table
but the breakpoint code (5BH) is not inserted into Target manory until the
E-EXECUTE camnand is entered. Hardware on the Control module detects the
breakpoint code acrl forces the breakpoint to occur. Breakpoint codes are
ranoved from Target memory when any type breakpoint occurs, but ranain in
the breakpoint table until the user clears them. If an attempt is made to .
set more than eight software breakpoints, then an error message is printed.
Software breakpoints may only be set on instruction boundaries. If a
software breakpoint is set at an address which is not the first byte of 'an
instruction, it will not be recognized and the instruction will be executed
incorrectly.