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BR


      format  BR expr 
    
 Description  Clears the break count of the expr-th breakpoint.
              If the character '*' is specified for expr, the break count of all software breaks
              Will be cleared.

Hardware break

The
hardware break monitors the occurrence of a specified bus cycle with hardware external to the CPU, and interrupts execution of the user program by raising the NMI to the CPU when the target bus cycle occurs.
The following bus cycle conditions can be set.
Address bus
Function code
Read / Write
Access data width
Access count

Up to 3 hardware breaks can be set, and they are called channel 0, channel 1, and channel 2, respectively.

Note that a break occurs after the bus cycle occurs and after the access ends. For example, if it is a write access, writing has already been completed at the time of the break.
Also note that the MC68000 prefetches program code and movem instruction data. In particular, if a hardware break is used for program execution, a break may occur before execution or a break may occur at an instruction that will not be executed (such as immediately after jmp). 

HB


      format  HB 
    
 Description  Lists the setting status of software breaks and hardware breaks. 



HB


      format  HB bpnum, adr [, mask [, cnt [,  [,  [, ]]]]] 
    
 Description  Set a breakpoint on the hardware break channel bpnum.
Adr-address
Mask-address mask (described later)
Cnt-breakcount
-Function code
-Access data width
-Read / Write 
    
bpnum is 0, 1, or 2.
adr is the address of MC68000.

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