From c4eaa944e22740464e6cafb5713c801369443c8f Mon Sep 17 00:00:00 2001 From: Irmen de Jong Date: Mon, 30 May 2022 23:37:41 +0200 Subject: [PATCH] thoughts --- docs/source/todo.rst | 50 ++++++++++++++++++++++++++++++++++---------- 1 file changed, 39 insertions(+), 11 deletions(-) diff --git a/docs/source/todo.rst b/docs/source/todo.rst index 082f24d60..d1c247f37 100644 --- a/docs/source/todo.rst +++ b/docs/source/todo.rst @@ -3,6 +3,11 @@ TODO For next release ^^^^^^^^^^^^^^^^ +- cx16 diskio: use cx16 MACPTR() in f_read() to load stuff faster? (see its use in X16edit to fast load blocks) + note that it might fail on non sdcard files so have to make graceful degradation +- pipe operator: (targets other than 'Virtual'): allow non-unary function calls in the pipe that specify the other argument(s) in the calls. Already working for VM target. +- add McCarthy evaluation to shortcircuit and/or expressions. First do ifs by splitting them up? Then do expressions that compute a value? +- Inliner: also inline function call expressions, and remove it from the StatementOptimizer ... @@ -17,8 +22,6 @@ Future Things and Ideas ^^^^^^^^^^^^^^^^^^^^^^^ Compiler: -- add McCarthy evaluation to shortcircuit and/or expressions. First do ifs by splitting them up? Then do expressions that compute a value? -- Inliner: also inline function call expressions, and remove it from the StatementOptimizer - vm: implement remaining sin/cos functions in math.p8 - vm: somehow deal with asmsubs otherwise the vm IR can't fully encode all of prog8 - vm: don't store symbol names in instructions to make optimizing the IR easier? but what about jumps to labels. And it's no longer readable by humans. @@ -38,7 +41,13 @@ Compiler: (but we lose the optimizing aspect of the assembler where it strips out unused code. There's not really a dynamic switch possible as all assembly lib code is static and uses one or the other) - Zig-like try-based error handling where the V flag could indicate error condition? and/or BRK to jump into monitor on failure? (has to set BRK vector for that) -- add special (u)word array type (or modifier?) that puts the array into memory as 2 separate byte-arrays 1 for LSB 1 for MSB -> allows for word arrays of length 256 +- add special (u)word array type (or modifier?) that puts the array into memory as 2 separate byte-arrays 1 for LSB 1 for MSB -> allows for word arrays of length 256 and faster indexing +- ast: don't rewrite by-reference parameter type to uword, but keep the original type (str, array) + BUT that makes the handling of these types different between the scope they are defined in, and the + scope they get passed in by reference... unless we make str and array types by-reference ALWAYS? BUT that + makes simple code accessing them in the declared scope very slow because that then has to always go through + the pointer rather than directly referencing the variable symbol in the generated asm.... + Libraries: @@ -48,20 +57,19 @@ Libraries: - optimize several inner loops in gfx2 even further? - add modes 2 and 3 to gfx2 (lowres 4 color and 16 color)? - add a flood fill routine to gfx2? -- diskio: use cx16 MACPTR() in f_read() to load stuff faster? (see its use in X16edit to fast load blocks) - note that it might fail on non sdcard files so have to make graceful degradation + Expressions: -- pipe operator: (targets other than 'Virtual'): allow non-unary function calls in the pipe that specify the other argument(s) in the calls. - rethink the whole "isAugmentable" business. Because the way this is determined, should always also be exactly mirrorred in the AugmentableAssignmentAsmGen or you'll get a crash at code gen time. - note: new ast PtAssignment already has no knowledge about this anymore. + note: the new Ast doesn't need this any more so maybe we can get rid of it altogether in the old AST - but it's still used for something in the UnusedCodeRemover. - can we get rid of pieces of asmgen.AssignmentAsmGen by just reusing the AugmentableAssignment ? generated code should not suffer -- rewrite expression tree evaluation suchthat it doesn't use an eval stack but flatten the tree into linear code that uses a fixed number of predetermined value 'variables'? +- rewrite expression tree evaluation such that it doesn't use an eval stack but flatten the tree into linear code that uses a fixed number of predetermined value 'variables'? "Three address code" was mentioned. https://en.wikipedia.org/wiki/Three-address_code these variables have to be unique for each subroutine because they could otherwise be interfered with from irq routines etc. + The VM IL solves this already (by using unlimited registers) but still lacks a translation to 6502. - this removes the need for the BinExprSplitter? (which is problematic and very limited now) - and perhaps as well the assignment splitting in BeforeAsmAstChanger too + and perhaps the assignment splitting in BeforeAsmAstChanger too Optimizations: @@ -71,7 +79,27 @@ Optimizations: - translateUnaryFunctioncall() in BuiltinFunctionsAsmGen: should be able to assign parameters to a builtin function directly from register(s), this will make the use of a builtin function in a pipe expression more efficient without using a temporary variable compare ``aa = startvalue(1) |> sin8u() |> cos8u() |> sin8u() |> cos8u()`` versus: ``aa = cos8u(sin8u(cos8u(sin8u(startvalue(1)))))`` the second one contains no sta cx16.r9L in between. -- AssignmentAsmGen.assignExpression() -> better code gen for assigning boolean comparison expressions +- AssignmentAsmGen.assignExpression() -> improve code gen for assigning boolean comparison expressions + Check what the vm target does here, maybe just do this as part of the vm -> 6502 codegen. - when a for loop's loopvariable isn't referenced in the body, and the iterations are known, replace the loop by a repeatloop but we have no efficient way right now to see if the body references a variable. -- introduce byte-index operator to avoid index multiplications in loops over arrays? see github issue #4 + + +STRUCTS again? +-------------- + +What if we were to re-introduce Structs in prog8? Some thoughts: + +- can contain only numeric types (byte,word,float) - no nested structs, no reference types (strings, arrays) inside structs +- is just some syntactic sugar for a scoped set of variables -> ast transform to do exactly this before codegen +- no arrays of struct -- because too slow on 6502 to access those, rather use struct of arrays instead. + can we make this a compiler/codegen only issue? i.e. syntax is just as if it was an array of structs? + or make it explicit in the syntax so that it is clear what the memory layout of it is. +- ability to assign struct variable to another? this is slow but can be quite handy sometimes. + however how to handle this in a function that gets the struct passed as reference? Don't allow it there? (there's no pointer dereferencing concept in prog8) +- ability to be passed as argument to a function (by reference)? + however there is no typed pointer in prog8 at the moment so this can't be implemented in a meaningful way yet, + because there is no way to reference it as the struct type again. (current ast gets the by-reference parameter + type replaced by uword) + So-- maybe don't replace the parameter type in the ast? Should fix that for str and array types as well then +