Subversion Repositories tv80

The tvs80 test was ported from Brian Porcella's environment, and as
such has some specific dependencies.  In particular, it is dependent
on the as80.exe DOS assembler.

To get this to build under Linux requires using the DOSBOX DOS
emulator.  Developent is currently being done with version 0.60.

To build and run the tvs80 test:

chdir tests/tvs80
./build
cd ../..
scripts/run2 tvs80

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Verification Status
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test ld_110 fails.  Code executed by ld_110 is:

ld_110:         ld      a,data_55
                ld      i,a
                ld      a,0
                ld      a,i
                jr      nz,ld_111

This puts a constant pattern in the A register, moves A into the interrupt
page register, clears A, then moves I back to A.  This looks like it's testing
for a side-effect in the original Z80, because moving data to the interrupt
page shouldn't clear the Z flag, but the test is expecting this.

Tests ld_110 through ld_116 all appear to test for the same behavior.

SP Increment/Decrement:
Tests inc_60 and dec_52 look like they test for the increment and
decrement instructions decrementing both halves of the SP register;
i.e. SP = SP - 0101 instead of SP = SP - 0001

Fixed these tests by setting the initial value of SP to +/- 100