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Improve test coverage. One failing test.

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Cat's Eye Technologies 2014-04-11 11:04:35 +01:00
parent 3ff96a0353
commit 5a49382ad4
1 changed files with 58 additions and 28 deletions
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doc/Analyzing.markdown
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@ -19,7 +19,8 @@ routine.
= NamedLocation Nothing "score": UpdatedWith A
A routine cannot expect registers which a called routine does not
preserve, to be preserved.
preserve, to be preserved. We say the called routine "poisons" those
registers.
| assign byte border_colour 4000
| reserve byte score
@ -35,7 +36,8 @@ preserve, to be preserved.
| }
? routine 'main' does not preserve 'A'
But if it does it can.
But if a called routine does preserve those registers, the caller can
continue to use them after calling the routine.
| assign byte border_colour 4000
| reserve byte score
@ -60,7 +62,8 @@ But if it does it can.
= X: UpdatedWith (Immediate 1)
= NamedLocation Nothing "score": UpdatedWith X
We can't expect to stay named variables to stay unmodified either.
Not only registers, but also named variables, can be poisoned by a called
routine.
| reserve byte score
| routine update_score
@ -74,8 +77,9 @@ We can't expect to stay named variables to stay unmodified either.
| }
? routine 'main' does not preserve 'NamedLocation Nothing "score"'
What the solution to the above is to notate `update_score` as intentionally
modifying score, as an "output" of the routine.
Of course, the difference between poisoning and intentionally modifying a
storage location is a matter of intent. The solution to the above is to
explicitly notate `update_score` as an "output" of the routine.
| assign byte border_colour 4000
| reserve byte score
@ -236,11 +240,9 @@ Poisoning a high byte or low byte of a word poisons the whole word.
| }
? routine 'main' does not preserve 'NamedLocation Nothing "score"'
| assign vector cinv 788
| reserve vector save_cinv
|
Some more tests...
| assign word position $fb
|
| reserve byte value
|
| routine reset_position {
@ -250,7 +252,7 @@ Poisoning a high byte or low byte of a word poisons the whole word.
| sta >position
| }
|
| routine our_cinv {
| routine main {
| inc value
| lda value
| ldy #0
@ -259,27 +261,9 @@ Poisoning a high byte or low byte of a word poisons the whole word.
| jsr reset_position
| } else {
| }
| jmp (save_cinv)
| }
|
| routine main {
| jsr reset_position
| sei {
| copy cinv save_cinv
| copy routine our_cinv to cinv
| }
| clc
| repeat bcc { }
| }
= main ([])
= A: PoisonedWith (Immediate 4)
= FlagC: UpdatedWith (Immediate 0)
= NamedLocation Nothing "cinv": UpdatedWith (Immediate 7)
= NamedLocation Nothing "position": PoisonedWith A
= NamedLocation Nothing "save_cinv": UpdatedWith (NamedLocation Nothing "cinv")
=
= our_cinv ([])
= A: PoisonedWith (Immediate 4)
= Y: UpdatedWith (Immediate 0)
= IndirectIndexed (NamedLocation (Just Word) "position") Y: UpdatedWith A
= NamedLocation Nothing "position": PoisonedWith A
@ -288,3 +272,49 @@ Poisoning a high byte or low byte of a word poisons the whole word.
= reset_position ([])
= A: UpdatedWith (Immediate 4)
= NamedLocation Nothing "position": UpdatedWith A
| assign word position $fb
| reserve byte value
|
| routine reset_position {
| lda #$00
| sta <position
| lda #$04
| sta >position
| }
|
| routine main {
| inc value
| lda value
| ldy #0
| sta (position), y
| if beq {
| jsr reset_position
| } else {
| }
| sta value
| }
? routine 'main' does not preserve 'A'
| assign word position $fb
| reserve byte value
|
| routine reset_position {
| lda #$00
| sta <position
| lda #$04
| sta >position
| }
|
| routine main {
| inc value
| lda value
| ldy #0
| sta (position), y
| jsr reset_position
| if beq {
| } else {
| sta value
| }
| }
? routine 'main' does not preserve 'A'