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Subtract word (constant or memory location) from word memory location.

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This commit is contained in:
Chris Pressey 2017-12-13 14:07:59 +00:00
parent 1478db0fb4
commit 5f535c963e
5 changed files with 124 additions and 2 deletions
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1
HISTORY.md
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@ -9,6 +9,7 @@ History of SixtyPical
in a `copy` to a vector is a routine that is defined further down in the source.
* Initialized `word` memory locations.
* Can `copy` a literal word to a word table.
* Subtract word (constant or memory location) from word memory location.
* Fixed bug which was preventing `if` branches to diverge in what they initialized,
if it was already initialized when going into the `if`.
* Fixed a bug which was making it crash when trying to analyze `repeat forever` loops.

10
src/sixtypical/analyzer.py
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@ -273,9 +273,15 @@ class Analyzer(object):
else:
self.assert_type(TYPE_WORD, dest)
elif opcode == 'sub':
self.assert_type(TYPE_BYTE, src, dest)
context.assert_meaningful(src, dest, FLAG_C)
context.set_written(dest, FLAG_Z, FLAG_N, FLAG_C, FLAG_V)
if src.type == TYPE_BYTE:
self.assert_type(TYPE_BYTE, src, dest)
context.set_written(dest, FLAG_Z, FLAG_N, FLAG_C, FLAG_V)
else:
self.assert_type(TYPE_WORD, src, dest)
context.set_written(dest, FLAG_Z, FLAG_N, FLAG_C, FLAG_V)
context.set_touched(REG_A)
context.set_unmeaningful(REG_A)
elif opcode in ('inc', 'dec'):
self.assert_type(TYPE_BYTE, dest)
context.assert_meaningful(dest)

20
src/sixtypical/compiler.py
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@ -230,6 +230,26 @@ class Compiler(object):
self.emitter.emit(SBC(Immediate(Byte(src.value))))
else:
self.emitter.emit(SBC(Absolute(self.labels[src.name])))
elif isinstance(dest, LocationRef) and src.type == TYPE_WORD and dest.type == TYPE_WORD:
if isinstance(src, ConstantRef):
dest_label = self.labels[dest.name]
self.emitter.emit(LDA(Absolute(dest_label)))
self.emitter.emit(SBC(Immediate(Byte(src.low_byte()))))
self.emitter.emit(STA(Absolute(dest_label)))
self.emitter.emit(LDA(Absolute(Offset(dest_label, 1))))
self.emitter.emit(SBC(Immediate(Byte(src.high_byte()))))
self.emitter.emit(STA(Absolute(Offset(dest_label, 1))))
elif isinstance(src, LocationRef):
src_label = self.labels[src.name]
dest_label = self.labels[dest.name]
self.emitter.emit(LDA(Absolute(dest_label)))
self.emitter.emit(SBC(Absolute(src_label)))
self.emitter.emit(STA(Absolute(dest_label)))
self.emitter.emit(LDA(Absolute(Offset(dest_label, 1))))
self.emitter.emit(SBC(Absolute(Offset(src_label, 1))))
self.emitter.emit(STA(Absolute(Offset(dest_label, 1))))
else:
raise UnsupportedOpcodeError(instr)
else:
raise UnsupportedOpcodeError(instr)
elif opcode == 'inc':

54
tests/SixtyPical Analysis.md
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@ -593,6 +593,60 @@ Can't `sub` to a memory location that isn't writeable.
| }
? ForbiddenWriteError: a in main
You can `sub` a word constant from a word memory location.
| word score
| routine main
| inputs a, score
| outputs score
| trashes a, c, z, v, n
| {
| st on, c
| sub score, 1999
| }
= ok
`sub`ing a word constant from a word memory location trashes `a`.
| word score
| routine main
| inputs a, score
| outputs score, a
| trashes c, z, v, n
| {
| st on, c
| sub score, 1999
| }
? UnmeaningfulOutputError: a in main
You can `sub` a word memory location from another word memory location.
| word score
| word delta
| routine main
| inputs score, delta
| outputs score
| trashes a, c, z, v, n
| {
| st off, c
| sub score, delta
| }
= ok
`sub`ing a word memory location from a word memory location trashes `a`.
| word score
| word delta
| routine main
| inputs score, delta
| outputs score
| trashes c, z, v, n
| {
| st off, c
| sub score, delta
| }
? ForbiddenWriteError: a in main
### inc ###
Location must be initialized and writeable.

41
tests/SixtyPical Compilation.md
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@ -895,6 +895,47 @@ Adding a word memory location to another word memory location.
= $081D STA $0822
= $0820 RTS
Subtracting a constant word from a word memory location.
| word score
| routine main
| inputs score
| outputs score
| trashes a, c, z, v, n
| {
| st on, c
| sub score, 1999
| }
= $080D SEC
= $080E LDA $081F
= $0811 SBC #$CF
= $0813 STA $081F
= $0816 LDA $0820
= $0819 SBC #$07
= $081B STA $0820
= $081E RTS
Subtracting a word memory location from another word memory location.
| word score
| word delta
| routine main
| inputs score, delta
| outputs score
| trashes a, c, z, v, n
| {
| st on, c
| sub score, delta
| }
= $080D SEC
= $080E LDA $0821
= $0811 SBC $0823
= $0814 STA $0821
= $0817 LDA $0822
= $081A SBC $0824
= $081D STA $0822
= $0820 RTS
### Buffers and Pointers
Load address into pointer.