better codegen for call() function

codeGenCpu6502/src/prog8/codegen/cpu6502/BuiltinFunctionsAsmGen.kt

@@ -266,23 +266,40 @@ internal class BuiltinFunctionsAsmGen(private val program: PtProgram,
     }
 
     private fun funcCall(fcall: PtBuiltinFunctionCall) {
+        // note: the routine can return a word value (in AY)
         val constAddr = fcall.args[0].asConstInteger()
         if(constAddr!=null) {
             asmgen.out("  jsr  ${constAddr.toHex()}")
-        } else {
+            return
-            asmgen.assignExpressionToRegister(fcall.args[0], RegisterOrPair.AY)     // jump address
-            asmgen.out("""
-              sta  (+)+1
-              sty  (+)+2
-+             jsr  0       ; modified""")
-            // TODO: avoid using modifying code here by pushing return address on the stack manually and use JMP (INDIRECT) ?  And if it's just a variable, simply JMP (variable) !
-            // TODO: also do this for CallFar below!
         }
 
-        // note: the routine can return a word value (in AY)
+        val identifier = fcall.args[0] as? PtIdentifier
+        if(identifier!=null) {
+            asmgen.out("""
+                ; push a return address so the jmp becomes indirect jsr
+                lda  #>((+)-1)
+                pha
+                lda  #<((+)-1)
+                pha
+                jmp  (${asmgen.asmSymbolName(identifier)})
++""")
+            return
+        }
+
+        asmgen.assignExpressionToVariable(fcall.args[0], asmgen.asmVariableName("P8ZP_SCRATCH_W2"), DataType.UWORD)     // jump address
+        asmgen.out("""
+                ; push a return address so the jmp becomes indirect jsr
+                lda  #>((+)-1)
+                pha
+                lda  #<((+)-1)
+                pha
+                jmp  (P8ZP_SCRATCH_W2)
++""")
     }
 
     private fun funcCallFar(fcall: PtBuiltinFunctionCall, resultRegister: RegisterOrPair?) {
+        // TODO apply same optimizations here as used on call() codegen above
+
         if(asmgen.options.compTarget.name != "cx16")
             throw AssemblyError("callfar only works on cx16 target at this time")
 

compiler/src/prog8/compiler/astprocessing/AstChecker.kt

@@ -1346,7 +1346,7 @@ internal class AstChecker(private val program: Program,
             if(target.name=="call") {
                 if(args[0] is AddressOf)
                     errors.err("can't call this indirectly, just use normal function call syntax", args[0].position)
-                if(args[0] is IdentifierReference) {
+                else if(args[0] is IdentifierReference) {
                     val callTarget = (args[0] as IdentifierReference).targetStatement(program)
                     if(callTarget !is VarDecl)
                         errors.err("can't call this indirectly, just use normal function call syntax", args[0].position)

compiler/test/ast/TestSubroutines.kt

@@ -92,8 +92,11 @@ main {
 main {
     sub start() {
         uword func = 12345
+        uword[] pointers = [1234,6789]
         void call(func)        ; ok
         void call(12345)       ; ok
+        void call(pointers[1]) ; ok
+        void call(cx16.r0+10)  ; ok
         cx16.r0 = call(func)   ; ok
         void call(&start)      ; error
         void call(start)       ; error

docs/source/todo.rst

@@ -5,9 +5,8 @@ Regenerate skeleton doc files.
 
 "invalid number of arguments" -> print the list of missing arguments
 
-call() asm gen in funcCall() could be improved by not using modifying code , see the TODO.
+callfar() should allow setting an argument in the X register as well? + similar optimizations that call() got.
 
-callfar() should allow setting an argument in the X register as well?
 
 Add a new SublimeText syntax file for prog8, and also install this for bat: https://github.com/sharkdp/bat?tab=readme-ov-file#adding-new-syntaxes--language-definitions
 
@@ -21,6 +20,7 @@ Future Things and Ideas
 ^^^^^^^^^^^^^^^^^^^^^^^
 Compiler:
 
+- AST weirdness: why is call(...) a normal FunctionCallStatement and not a BuiltinFunctionCall?  What does ror() produce for instance?
 - Can we support signed % (remainder) somehow?
 - Don't add "random" rts to %asm blocks but instead give a warning about it? (but this breaks existing behavior that others already depend on... command line switch? block directive?)
 - IR: implement missing operators in AssignmentGen  (array shifts etc)

examples/test.p8

@@ -1,116 +1,42 @@
 %import textio
 %import string
 %import compression
+%import test_stack
 %zeropage basicsafe
 %option no_sysinit
 
 main {
     sub start() {
-        ubyte[] rle = [
+        test_stack.test()
-            5, '1', '2', '3', '4', '5', '6',
+        example(function1, 42)
-            3, 'a', 'b', 'c', 'd',
+        example(function1, 99)
-            0, 'z',
+        example(function2, 42)
-            3, '1', '2', '3','4',
+        example(function2, 99)
-            -5, '=',
+        test_stack.test()
-            -127, '+',
+        cx16.r0++
-            4, '!', '@', '#', '$', '%',
-            128]
 
-        str @shared result = "\x00"*200
+        sub function1(ubyte arg) {
-
+            txt.print("function 1 arg=")
-        uword ptr = &rle
+            txt.print_ub(arg)
-
-        txt.print_uw(compression.decode_rle_srcfunc(callback, result, len(result)))
-        txt.nl()
-        txt.print_uw(compression.decode_rle(rle, result, len(result)))
-        txt.nl()
-        txt.print_uw(string.length(result))
-        txt.nl()
-        txt.print(result)
-        txt.nl()
-        txt.print_uwhex(&result, true)
-        txt.nl()
-
-        sub callback() -> ubyte {
-            ubyte x = @(ptr)
-            ptr++
-            return x
-        }
-
-
-        ubyte[256] buffer
-        ubyte[256] buffer2
-        uword bufptr = &buffer
-        uword outputsize=0
-
-        sub outputter(ubyte value) {
-            @(bufptr) = value
-            bufptr++
-            outputsize++
-        }
-
-        str input = iso:"123456aaaaabcdzzz1234======++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++!@#$%"
-        ubyte[31] expected_rle = [$5, $31, $32, $33, $34, $35, $36, $fc, $61, $2, $62, $63, $64, $fe, $7a, $3, $31, $32, $33, $34, $fb, $3d, $81, $2b, $4, $21, $40, $23, $24, $25, $80]
-        txt.print(input)
-        txt.nl()
-
-        compression.encode_rle_outfunc(input, len(input), outputter, true)
-        txt.print_uw(outputsize)
-        txt.nl()
-        if outputsize!=len(expected_rle)
-            txt.print("wrong rle size!\n")
-
-        txt.print("\ncompare rle (encode using callback):\n")
-        for cx16.r9L in 0 to len(expected_rle)-1 {
-;            txt.print_ub0(cx16.r9L)
-;            txt.spc()
-;            txt.print_ubhex(expected_rle[cx16.r9L], false)
-;            txt.spc()
-;            txt.print_ubhex(buffer[cx16.r9L], false)
-            if buffer[cx16.r9L] != expected_rle[cx16.r9L]
-                txt.print(" wrong rle data!")
-;            txt.nl()
-        }
-        txt.nl()
-
-        cx16.r0 = compression.decode_rle(buffer, buffer2, len(buffer2))
-        if cx16.r0 != len(input)
-            txt.print("wrong decompress result!\n")
-        else {
-            txt.print("good result: ")
-            txt.print(buffer2)
             txt.nl()
         }
 
-
+        sub function2(ubyte arg) {
-        buffer[0] = buffer[1] = buffer[2] = 128
+            txt.print("function 2 arg=")
-        outputsize = compression.encode_rle(input, len(input), buffer, true)
+            txt.print_ub(arg)
-        txt.print_uw(outputsize)
-        txt.nl()
-        if outputsize!=len(expected_rle)
-            txt.print("wrong rle size!\n")
-
-        txt.print("\ncompare rle (encode into buffer):\n")
-        for cx16.r9L in 0 to len(expected_rle)-1 {
-;            txt.print_ub0(cx16.r9L)
-;            txt.spc()
-;            txt.print_ubhex(expected_rle[cx16.r9L], false)
-;            txt.spc()
-;            txt.print_ubhex(buffer[cx16.r9L], false)
-            if buffer[cx16.r9L] != expected_rle[cx16.r9L]
-                txt.print(" wrong rle data!")
-;            txt.nl()
-        }
-        txt.nl()
-
-        cx16.r0 = compression.decode_rle(buffer, buffer2, len(buffer2))
-        if cx16.r0 != len(input)
-            txt.print("wrong decompress result!\n")
-        else {
-            txt.print("good result: ")
-            txt.print(buffer2)
             txt.nl()
         }
+
+        sub example(uword function, ubyte value) {
+
+            %asm {{
+                lda  p8v_value
+            }}
+
+            call(function)
+            cx16.r1 = function+10
+            call(cx16.r1-10)
+        }
     }
 }