Truong Than
CS644
HW1a.6 : Draw a picture of memory, showing the code areas and 4 stacks, in
xinu.txt, or on paper.
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Here is what we get from the gdb done in hw1a.5:
(gdb) p/x proctab[0].paddr
$7 = 0x100170
(gdb) p/x proctab[49].paddr
$8 = 0x1018a8
(gdb) p/x proctab[48].paddr
$9 = 0x100a0c
(gdb) p/x proctab[47].paddr
$10 = 0x100970
(gdb) p/x proctab[0].pbase
$11 = 0x3ffffc
(gdb) p/x proctab[49].pbase
$12 = 0x3fd7f8
(gdb) p/x proctab[48].pbase
$13 = 0x3f87f8
(gdb) p/x proctab[47].pbase
$14 = 0x3f5ff8

The lowest extent of the stacks represted by "v" in the below diagram of
the stack areas.
(gdb) p/x proctab[0].plimit
$15 = 0x3fd800
(gdb) p/x proctab[49].plimit
$16 = 0x3f87fc
(gdb) p/x proctab[48].plimit
$17 = 0x3f5ffc
(gdb) p/x proctab[47].plimit
$18 = 0x3f37fc

Code Area:

     null proc	   prod		cons	   main
--|------------|------------|----------|-------------|--------------
 0x100170     0x100970	   0x100A0C   0x1018A8


Stack Area, i.e., continuing the above picture after a big gap--

        <-- prod|   <-- cons|	     <-- main| <-- null proc|
----|v----------|v----------|v---------------|v-------------|-|0x400000
    0x3F37F8	0x3F5FF8   0x3F87F8	   0x3FD7F8     0x3FFFFC

eoneil note: 0x100000 is 1MB and 0x4000000 is 4MB, the top of usable memory 
on the SAPC.  Below 0x100000 is the frame buffer and BIOS, and also another
area of usable memory which contains the Tutor code. So we have 3MB of
memory for downloaded programs.