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mirror of https://github.com/catseye/SixtyPical.git synced 2024-11-25 23:49:17 +00:00

Deal with the inputs/outputs of buffers, in a weak way.

This commit is contained in:
Chris Pressey 2017-12-01 15:10:16 +00:00
parent d84566a880
commit 6afbf581f7
4 changed files with 37 additions and 16 deletions

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@ -6,6 +6,7 @@ History of SixtyPical
* Explicit word literals prefixed with `word` token.
* Can `copy` literals into user-defined destinations.
* Fixed bug where loop variable wasn't being checked at end of `repeat` loop.
* `buffer` and `pointer` types.
* `copy ^` syntax to load the addr of a buffer into a pointer.
* `copy []+y` syntax to read and write values to and from memory through a pointer.

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@ -41,9 +41,10 @@ Documentation
TODO
----
Insist the buffer being read or written to through pointer, appears in approporiate set.
### Add to pointer.
Add to pointer.
And then write a little demo "game" where you can move a block around the screen with
the joystick.
### `word table` and `vector table` types
@ -58,6 +59,9 @@ are trashed inside the block.
### And at some point...
* `copy x, [ptr] + y`
* Maybe even `copy [ptra] + y, [ptrb] + y`, which can be compiled to indirect LDA then indirect STA!
* Check that the buffer being read or written to through pointer, appears in approporiate inputs or outputs set.
* initialized `byte table` memory locations
* always analyze before executing or compiling, unless told not to
* `trash` instruction.

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@ -1176,9 +1176,20 @@ Can't `copy` from a `word` to a `byte`.
Buffers and pointers.
Note that `^buf` is not considered "reading" buf, so does not require it in `inputs`.
TODO: If reading from it through a pointer, it *should* require it in `inputs`.
TODO: If writing to it through a pointer, it *should* require it in `outputs`.
Note that `^buf` is a constant value, so it by itself does not require `buf` to be
listed in any input/output sets.
However, if the code reads from it through a pointer, it *should* be in `inputs`.
Likewise, if the code writes to it through a pointer, it *should* be in `outputs`.
Of course, unless you write to *all* the bytes in a buffer, some of those bytes
might not be meaningful. So how meaningful is this check?
This is an open problem.
For now, convention says: if it is being read, list it in `inputs`, and if it is
being modified, list it in both `inputs` and `outputs`.
Write literal through a pointer.
@ -1186,7 +1197,8 @@ Write literal through a pointer.
| pointer ptr
|
| routine main
| outputs y //, buf
| inputs buf
| outputs y, buf
| trashes a, z, n, ptr
| {
| ld y, 0
@ -1201,7 +1213,8 @@ It does use `y`.
| pointer ptr
|
| routine main
| // outputs buf
| inputs buf
| outputs buf
| trashes a, z, n, ptr
| {
| copy ^buf, ptr
@ -1216,8 +1229,8 @@ Write stored value through a pointer.
| byte foo
|
| routine main
| inputs foo
| outputs y //, buf
| inputs foo, buf
| outputs y, buf
| trashes a, z, n, ptr
| {
| ld y, 0
@ -1233,7 +1246,7 @@ Read through a pointer.
| byte foo
|
| routine main
| // inputs buf
| inputs buf
| outputs foo
| trashes a, y, z, n, ptr
| {

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@ -342,7 +342,9 @@ goto.
| }
= 00c0a0c84c06c060a2c860
Buffers and pointers.
### Buffers and Pointers
Load address into pointer.
| buffer[2048] buf
| pointer ptr @ 254
@ -357,12 +359,13 @@ Buffers and pointers.
| }
= 00c0a000a90b85fea9c085ff60
Writing literal through a pointer.
Write literal through a pointer.
| buffer[2048] buf
| pointer ptr @ 254
|
| routine main
| inputs buf
| outputs buf, y
| trashes a, z, n, ptr
| {
@ -379,8 +382,8 @@ Write stored value through a pointer.
| byte foo
|
| routine main
| inputs foo
| outputs y //, buf
| inputs foo, buf
| outputs y, buf
| trashes a, z, n, ptr
| {
| ld y, 0
@ -389,14 +392,14 @@ Write stored value through a pointer.
| }
= 00c0a000a91085fea9c085ffad12c091fe60
Reading through a pointer.
Read through a pointer.
| buffer[2048] buf
| pointer ptr @ 254
| byte foo
|
| routine main
| // inputs buf
| inputs buf
| outputs y, foo
| trashes a, z, n, ptr
| {