Msim 64bit incorrectly handles memory breakpoints

[Peter Júnoš]

Memory breakpoints in 64bit environment are always set as of type "-w".

Steps, how it was done:
[msim] break 0x2000 2 r
[msim] dumpbreak
Address Mode Hits
---------- ---- --------------------
0x00002000 -w 0

Stopping on memory breakpoint fails with error messages:
"<msim> gdb: Bad file descriptor"

[Peter Júnoš (petoju)]

This bug is also present in MSIM mainline from bzr://d3s.mff.cuni.cz/msim/mainline

[msim] break 0x1000 10 rw
[msim] dumpbreak
[address ] [mode] [hits ]
0x0000000000001000 -w 0

Mainline MSIM also fails, when reaching breakpoint and simulation ends:
<msim> Fault: Unexpected physical memory breakpoint kind
Aborted (core dumped)

However, this bug is does not appear in MSIM stable (bzr://d3s.mff.cuni.cz/msim/stable-1.3). That version uses different commands and they work as expected:

[msim] break 0x1000 rw
[msim] bd
Address Mode Hits
---------- ---- --------------------
0x00001000 rw 0
[msim] continue

Debug: Written to address 0x1000

[msim]