`inc` and `dec` on a known range usually keeps it known, now.
Chris Pressey
3 years ago
| 6 | 6 |
* Syntactically, `goto` may only appear at the end of a block.
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| 7 | 7 |
It need no longer be the final instruction in a routine,
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| 8 | 8 |
as long as the type context is consistent at every exit.
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|
9 |
* When the range of a location is known, `inc` and `dec`
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|
10 |
on it will usually shift the known instead of invalidating it.
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| 9 | 11 |
* `cmp` instruction can now perform a 16-bit unsigned comparison
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| 10 | 12 |
of `word` memory locations (at the cost of trashing `a`.)
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| 11 | 13 |
* Fixed pathological memory use in the lexical scanner - should
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| 1 | 1 |
// Demonstrates vector tables.
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| 2 | 2 |
// Prints "AABAB".
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| 3 | 3 |
//
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| 4 | |
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| 5 | |
// TODO: this doesn't pass the analyzer currently, which suggests a bug.
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| 6 | |
//
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| 7 | |
// RangeExceededError: Possible range of x:byte (0, 255) exceeds
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| 8 | |
// acceptable range of vectors:vector table[32] (0, 31) (in main, line 57)
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| 9 | |
//
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| 10 | |
// (despite various attempts to work around by calling a setup routine, etc.)
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| 11 | |
// It should really be able to figure out that the range of x is 0..4 there.
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| 12 | 4 |
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| 13 | 5 |
vector routine
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| 14 | 6 |
trashes a, z, n
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| 596 | 596 |
else:
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| 597 | 597 |
self.assert_type(TYPE_BYTE, dest)
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| 598 | 598 |
context.set_written(dest, FLAG_Z, FLAG_N)
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| 599 | |
context.invalidate_range(dest)
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599 |
bottom = context.get_bottom_of_range(dest)
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600 |
top = context.get_top_of_range(dest)
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|
601 |
if opcode == 'inc':
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602 |
if bottom == top and top < 255:
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603 |
context.set_range(dest, bottom + 1, top + 1)
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else:
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605 |
context.invalidate_range(dest)
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606 |
elif opcode == 'dec':
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607 |
if bottom == top and bottom > 0:
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608 |
context.set_range(dest, bottom - 1, top - 1)
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|
609 |
else:
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|
610 |
context.invalidate_range(dest)
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|
611 |
else:
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|
612 |
raise NotImplementedError
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| 600 | 613 |
elif opcode in ('shl', 'shr'):
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| 601 | 614 |
context.assert_meaningful(dest, FLAG_C)
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| 602 | 615 |
if isinstance(dest, IndexedRef):
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| 760 | 760 |
| copy many + x, one
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| 761 | 761 |
| }
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| 762 | 762 |
? RangeExceededError
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|
763 |
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|
764 |
When the range of a location is known, incrementing or
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|
765 |
decrementing that location's value will shift the known
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|
766 |
range. It will not invalidate it unless the known range
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|
767 |
is at the limits of the possible ranges for the type.
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|
768 |
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|
769 |
| vector routine
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|
770 |
| trashes a, z, n
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|
771 |
| print
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|
772 |
|
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|
773 |
| vector (routine
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|
774 |
| trashes a, z, n)
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|
775 |
| table[32] vectors
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776 |
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777 |
| define main routine
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|
778 |
| inputs vectors, print
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|
779 |
| outputs vectors
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780 |
| trashes print, a, x, z, n, c
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|
781 |
| {
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|
782 |
| ld x, 0
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|
783 |
| inc x
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|
784 |
| copy print, vectors + x
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|
785 |
| }
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|
786 |
= ok
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|
787 |
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|
788 |
| vector routine
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|
789 |
| trashes a, z, n
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|
790 |
| print
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|
791 |
|
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|
792 |
| vector (routine
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|
793 |
| trashes a, z, n)
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|
794 |
| table[32] vectors
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|
795 |
|
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|
796 |
| define main routine
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|
797 |
| inputs vectors, print
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|
798 |
| outputs vectors
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|
799 |
| trashes print, a, x, z, n, c
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|
800 |
| {
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|
801 |
| ld x, 32
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|
802 |
| dec x
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|
803 |
| copy print, vectors + x
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|
804 |
| }
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|
805 |
= ok
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| 763 | 806 |
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| 764 | 807 |
### add ###
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| 765 | 808 |
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