v8_maintenance branch made

compiler/res/version.txt

@@ -1 +1 @@
-8.13
+8.14-dev

docs/source/todo.rst

@@ -1,89 +1,9 @@
-TODO
-====
 
-For next minor release
-^^^^^^^^^^^^^^^^^^^^^^
+This is the maintenance branch for Prog8 version 8, only important bugfixes will be made here.
+New development for version 9 and up is taking place in the master branch.
+
+TODO V8 maintenance fixes
+^^^^^^^^^^^^^^^^^^^^^^^^^
 ...
 
 
-For 9.0 major changes are being made in the "version_9" branch. Look there.
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-
-
-Need help with
-^^^^^^^^^^^^^^
-- atari target: more details details about the machine, fixing library routines. I have no clue whatsoever.
-- see the :ref:`portingguide` for details on what information is needed.
-
-
-Future Things and Ideas
-^^^^^^^^^^^^^^^^^^^^^^^
-Compiler:
-
-- ir: idea: (but LLVM IR simply keeps the variables, so not a good idea then?...): replace all scalar variables by an allocated register. Keep a table of the variable to register mapping (including the datatype)
-  global initialization values are simply a list of LOAD instructions.
-  Variables replaced include all subroutine parameters!  So the only variables that remain as variables are arrays and strings.
-- ir: mechanism to determine for chunks which registers are getting input values from "outside"
-- ir: mechanism to determine for chunks which registers are passing values out? (i.e. are used again in another chunk)
-- ir: peephole opt: (maybe just integrate this in the variable/register allocator though?) renumber registers in chunks to start with 1 again every time (but keep entry values in mind!)
-- ir: peephole opt: (maybe just integrate this in the variable/register allocator though?) reuse registers in chunks (but keep result registers in mind that pass values out! and don't renumber registers above SyscallRegisterBase!)
-- ir: add more optimizations in IRPeepholeOptimizer
-- ir: for expressions with array indexes that occur multiple times, can we avoid loading them into new virtualregs everytime and just reuse a single virtualreg as indexer? (simple form of common subexpression elimination)
-- try to optimize newexpr a bit more? Although maybe just spend effort on a new codegen based on the IR.
-- PtAst/IR: more complex common subexpression eliminations
-- generate WASM to eventually run prog8 on a browser canvas? Use binaryen toolkit or my binaryen kotlin library?
-- can we get rid of pieces of asmgen.AssignmentAsmGen by just reusing the AugmentableAssignment ? generated code should not suffer
-- [problematic due to using 64tass:] better support for building library programs, where unused .proc shouldn't be deleted from the assembly?
-  Perhaps replace all uses of .proc/.pend/.endproc by .block/.bend will fix that with a compiler flag?
-  But all library code written in asm uses .proc already..... (textual search/replace when writing the actual asm?)
-  Once new codegen is written that is based on the IR, this point is mostly moot anyway as that will have its own dead code removal on the IR level.
-- 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) But the V flag is also set on certain normal instructions
-- For c128 target; put floating point variables in bank 1 to make the FP routines work (is this even worth it? very few people will use fp)
-
-Libraries:
-
-- fix the problems in atari target, and flesh out its libraries.
-- c128 target: make syslib more complete (missing kernal routines)?
-- c64: make the graphics.BITMAP_ADDRESS configurable (VIC banking)
-- optimize several inner loops in gfx2 even further?
-- add modes 3 and perhaps even 2 to gfx2 (lores 16 color and 4 color)?
-- add a flood fill (span fill/scanline fill) routine to gfx2?
-
-
-Expressions:
-
-- Once the evalstack-free expression codegen is in place, the Eval Stack can be removed from the compiler.
-    Machinedefinition, .p8 and .asm library files, all routines operationg on estack, and everything saving/restoring the X register related to this stack.
-- Or rewrite expression tree evaluation such that it doesn't use an eval stack but flatten the tree into linear code
-  that, for instance, uses a fixed number of predetermined value 'variables'?
-  The VM IL solves this already (by using unlimited registers) but that still lacks a translation to 6502.
-- this removes the need for the BinExprSplitter? (which is problematic and very limited now)
-  and perhaps the assignment splitting in  BeforeAsmAstChanger  too
-
-Optimizations:
-
-- VariableAllocator: can we think of a smarter strategy for allocating variables into zeropage, rather than first-come-first-served?
-  for instance, vars used inside loops first, then loopvars, then uwords used as pointers, then the rest
-- various optimizers skip stuff if compTarget.name==VMTarget.NAME.  Once 6502-codegen is done from IR code,
-  those checks should probably be removed, or be made permanent
-
-
-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. Codegen doesn't know about struct.
-- 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
-

examples/test.p8

@@ -1,16 +1,28 @@
+%import textio
 %zeropage basicsafe
 
 main {
 
     sub start() {
-        ubyte @shared foo = derp(99)
-    }
+        ubyte x8
+        ubyte x4
+        ubyte x3
+        ubyte result = x3 % x8
+        txt.print_ub(result)
+        txt.nl()
+        result = x3/x8
+        txt.print_ub(result)
+        txt.nl()
 
-    asmsub derp(ubyte xx @Y) -> ubyte @ A {
-        %asm {{
-            rts
-
-        }}
+        uword y8
+        uword y4
+        uword y3
+        uword wresult = y3 % y8
+        txt.print_uw(wresult)
+        txt.nl()
+        wresult = y3 / y8
+        txt.print_uw(wresult)
+        txt.nl()
     }
 }