====== MAME Debugger Breakpoint Commands ======


===== bpset =====

**Syntax:** ''bp[set] <address>[,<condition>[,<action>]]''

Sets a new execution breakpoint at the specified ''<address>''. The optional ''<condition>'' parameter lets you specify an expression that will be evaluated each time the breakpoint is hit. If the result of the expression is true (non-zero), the breakpoint will actually halt execution; otherwise, execution will continue with no notification. The optional ''<action>'' parameter provides a command that is executed whenever the breakpoint is hit and the ''<condition>'' is true. Note that you may need to embed the action within braces { } in order to prevent commas and semicolons from being interpreted as applying to the //bpset// command itself. Each breakpoint that is set is assigned an index which can be used in other breakpoint commands to reference this breakpoint.

**Examples:**

  * ''bp 1234'' -- Set a breakpoint that will halt execution whenever the ''PC'' is equal to ''1234''.
  * ''bp 23456,a0 == 0 && a1 == 0'' -- Set a breakpoint that will halt execution whenever the ''PC'' is equal to ''23456'' AND the expression ''(a0 == 0 && a1 == 0)'' is true.
  * ''bp 3456,1,{printf %%"A0=%08X\n"%%,a0; g}'' -- Set a breakpoint that will halt execution whenever the ''PC'' is equal to ''3456''. When this happens, print ''A0=<a0val>'' and continue executing.
  * ''bp 45678,a0==100,{a0 = ff; g}'' -- Set a breakpoint that will halt execution whenever the ''PC'' is equal to ''45678'' AND the expression ''(a0 == 100)'' is true. When that happens, set ''a0'' to ''ff'' and resume execution.
  * ''temp0 = 0; bp 567890,++temp0 >= 10'' -- Set a breakpoint that will halt execution whenever the ''PC'' is equal to ''567890'' AND the expression ''(++temp0 >= 10)'' is true. This effectively breaks only after the breakpoint has been hit 16 times.


===== bpclear =====

**Syntax:** ''bpclear [<bpnum>]''

The //bpclear// command clears a breakpoint. If ''<bpnum>'' is specified, only the requested breakpoint is cleared, otherwise all breakpoints are cleared.

**Examples:**

  * ''bpclear 3'' -- Clear breakpoint index 3.
  * ''bpclear'' -- Clear all breakpoints.


===== bpdisable =====

**Syntax:** ''bpdisable [<bpnum>]''

The //bpdisable// command disables a breakpoint. If ''<bpnum>'' is specified, only the requested breakpoint is disabled, otherwise all breakpoints are disabled. Note that disabling a breakpoint does not delete it, it just temporarily marks the breakpoint as inactive.

**Examples:**

  * ''bpdisable 3'' -- Disable breakpoint index 3.
  * ''bpdisable'' -- Disable all breakpoints.


===== bpenable =====

**Syntax:** ''bpenable [<bpnum>]''

The //bpenable// command enables a breakpoint. If ''<bpnum>'' is specified, only the requested breakpoint is enabled, otherwise all breakpoints are enabled.

**Examples:**

  * ''bpenable 3'' -- Enable breakpoint index 3.
  * ''bpenable'' -- Enable all breakpoints.


===== bplist =====

**Syntax:** ''bplist''

The //bplist// command lists all the current breakpoints, along with their index and any conditions or actions attached to them.