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GDB Remote Stub Backend for debugging an embedded ARM system via JTAG common hardware debug interfac

Motivation
==========
This tool has been created as part of our diploma project:
porting linux 2.6 on the arm9tdmi based microcontroller p2001 on
the evaluation board lpec2001 (http://www.mazbr.de/frames/products.html).
This tool is based on jtag-arm9 by Simon Wood.



Module structure
================
pp.[ch]:	parallel port interface
    pp_*	parallel port
    pp_ppdev_*	access via /dev/parport?
    pp_direct_*	access via port 0x387

jtag.[ch]:	tap+jtag+sc functions
    tapsm_*	tap state machine
    jtag_*	jtag
    sc_*	scan chain

ice.[ch]:	EmbeddedICE macrocell programming
    ice_*	EmbeddedICE

debug.[ch]:	debugging and register functions
    debug_*	debugging
    regs_*	registers

memory.[ch]:	memory functions
    memory_*	memory

lpec.[ch]:	lpec-p2001 specific functions
    lpec_*	lpec-p2001

jtag-arm.c:	command line client

gdb-jtag-arm.c:	GDB remote server



GDB Commands
============
required:
g				read registers
G<XX...>			write registers
m<addr>,<length>		read memory
M<addr>,<length>:<XX...>	write memory
c<addr>				continue
s<addr>				step

optional:
D				detach
i<addr>,<nnn>			cycle step
p<n...>=<r...>			write register
x<addr>,<length>:<XX...>	write mem (binary)
z<t>,<addr>,<length>		remove break or watchpoint
Z<t>,<addr>,<length>		insert break or watchpoint

t: 0=software breakpoint
   1=hardware breakpoint
   2=write watchpoint
   3=read watchpoint
   4=access watchpoint



JTAG chains
===========
with tms=? to	 		    	tms=0	tms=1

1111    1 0xF	Test-Logic Reset	0xC	0xF
1100      0xC	Run-Test/Idle		0xC	0x7

0111      0x7	Select-DR-Scan		0x6	0x4
0110 1    0x6	Capture-DR		0x2	0x1
0010      0x2	Shift-DR		0x2	0x1
0001  11  0x1	Exit1-DR		0x3	0x5
0011   1  0x3	Pause-DR		0x3	0x0
0000  1   0x0	Exit2-DR		0x2	0x5
0101      0x5	Update-DR		0xC	0x7

0100      0x4	Select-IR-Scan		0xE	0xF
1110 1    0xE	Capture-IR		0x9	0xA
1010      0xA	Shift-IR		0xA	0x9
1001  11  0x9	Exit1-IR		0xB	0xD
1011   1  0xB	Pause-IR		0xB	0x8
1000  1   0x8	Exit2-IR		0xA	0xD
1101      0xD	Update-IR		0xC	0x7

|||| |||\ 7:RESET
|||| ||\- 6:PAUSE
|||| |\-- 5:UPDATE
|||| \--- 4:CAPTURE
||||
|||\----- 3:IDLE
||\------ 2:SHIFT
|\------- 1:IR
\-------- 0:DR