Format of Turbo Debugger hardware breakpoint commands:
Offset	Size	Description	)
 00h	BYTE	command code
		00h install interrupt vectors
		01h get hardware capabilities
		02h enable hardware breakpoints
		03h disable hardware breakpoints
		04h set hardware breakpoint
		05h clear hardware breakpoint
		06h set I/O base address and reset hardware
		07h restore interrupt vectors
---command code 00h---
 01h	DWORD	pointer to Turbo Debugger entry point to be jumped to on
		  hardware breakpoint; call with CPU state the same as on
		  the breakpoint except for pushing AX and placing an entry
		  code (FFh if breakout button or breakpoint handle) in AH
---command code 04h---
 01h	BYTE	breakpoint type
		00h memory read
		01h memory write
		02h memory read/write
		03h I/O read
		04h I/O write
		05h I/O read/write
		06h instruction fetch
 02h	BYTE	address matching mode (see #01419)
 03h	DWORD	32-bit linear low address
 07h	DWORD	32-bit linear high address
 0Bh	WORD	pass count
 0Dh	BYTE	data size (01h, 02h, or 04h)
 0Eh	BYTE	source of matched bus cycle (01h CPU, 02h DMA, 03h either)
 0Fh	BYTE	data-matching mode (see #01419)
 10h	DWORD	low data value
 14h	DWORD	high data value
 18h	DWORD	data mask specifying which bits of the data are tested
---command code 05h---
 01h	BYTE	handle of breakpoint to clear (breakpoint returned from command
		  04h)
---command code 06h---
 01h	WORD	base address of hardware debugger board