From bba4f8450324012a8e4e1ba18b31f96992a31840 Mon Sep 17 00:00:00 2001
From: Irmen de Jong <irmen@razorvine.net>
Date: Tue, 22 Dec 2020 06:13:14 +0100
Subject: [PATCH] added target() function

---
 compiler/src/prog8/functions/BuiltinFunctions.kt | 15 +++++++++++++++
 docs/source/programming.rst                      |  7 +++++++
 docs/source/todo.rst                             |  1 -
 examples/test.p8                                 |  3 +--
 4 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/compiler/src/prog8/functions/BuiltinFunctions.kt b/compiler/src/prog8/functions/BuiltinFunctions.kt
index 8a7d0622f..967496b6e 100644
--- a/compiler/src/prog8/functions/BuiltinFunctions.kt
+++ b/compiler/src/prog8/functions/BuiltinFunctions.kt
@@ -6,6 +6,9 @@ import prog8.ast.expressions.*
 import prog8.ast.statements.StructDecl
 import prog8.ast.statements.VarDecl
 import prog8.compiler.CompilerException
+import prog8.compiler.target.C64Target
+import prog8.compiler.target.CompilationTarget
+import prog8.compiler.target.Cx16Target
 import kotlin.math.*
 
 
@@ -142,6 +145,7 @@ private val functionSignatures: List<FSignature> = listOf(
     FSignature("clear_irqd"  , false, emptyList(), null),
     FSignature("read_flags"  , false, emptyList(), DataType.UBYTE),
     FSignature("progend"     , true, emptyList(), DataType.UWORD),
+    FSignature("target"      , true, emptyList(), DataType.UBYTE, ::builtinTarget),
     FSignature("swap"        , false, listOf(FParam("first", NumericDatatypes), FParam("second", NumericDatatypes)), null),
     FSignature("memcopy"     , false, listOf(
                             FParam("from", IterableDatatypes + DataType.UWORD),
@@ -480,6 +484,17 @@ private fun builtinSgn(args: List<Expression>, position: Position, program: Prog
     return NumericLiteralValue(DataType.BYTE, constval.number.toDouble().sign.toInt().toShort(), position)
 }
 
+private fun builtinTarget(args: List<Expression>, position: Position, program: Program): NumericLiteralValue {
+    if (args.isNotEmpty())
+        throw SyntaxError("target requires no arguments", position)
+    val target = when(CompilationTarget.instance) {
+        is C64Target -> 64
+        is Cx16Target -> 16
+        else -> throw CompilerException("unrecognised compilation target")
+    }
+    return NumericLiteralValue(DataType.UBYTE, target, position)
+}
+
 private fun numericLiteral(value: Number, position: Position): NumericLiteralValue {
     val floatNum=value.toDouble()
     val tweakedValue: Number =
diff --git a/docs/source/programming.rst b/docs/source/programming.rst
index 67348966b..c935d7928 100644
--- a/docs/source/programming.rst
+++ b/docs/source/programming.rst
@@ -912,6 +912,13 @@ set_irqd()  /  clear_irqd()
 swap(x, y)
     Swap the values of numerical variables (or memory locations) x and y in a fast way.
 
+target()
+    Returns byte value designating the target machine that the program was compiled for.
+    The following return values are currently defined:
+
+    - 16 = compiled for CommanderX16 with 65C02 CPU
+    - 64 = compiled for Commodore-64 with 6502/6510 CPU
+
 progend()
     Returns the last address of the program in memory + 1.
     Can be used to load dynamic data after the program, instead of hardcoding something.
diff --git a/docs/source/todo.rst b/docs/source/todo.rst
index c1d1d5a66..4f1e0fe43 100644
--- a/docs/source/todo.rst
+++ b/docs/source/todo.rst
@@ -2,7 +2,6 @@
 TODO
 ====
 
-- add target() function that returns 16=cx16, 64=C64
 - Cx16 target: support full-screen 640x480 and 320x240 graphics? That requires our own custom graphics routines though to draw lines.
 - hoist all variable declarations up to the subroutine scope *before* even the constant folding takes place (to avoid undefined symbol errors when referring to a variable from another nested scope in the subroutine)
 - make it possible to use cpu opcodes such as 'nop' as variable names by prefixing all asm vars with something such as '_'
diff --git a/examples/test.p8 b/examples/test.p8
index 2ceb1fe8c..d6c4f9e94 100644
--- a/examples/test.p8
+++ b/examples/test.p8
@@ -83,8 +83,7 @@ _y  .byte 0
     }
 
     sub start () {
-        ubyte ss = withasm(derp(1), 33,66)
-        txt.print_ub(ss)
+        txt.print_ub(target())
         txt.chrout('\n')
 
 ;        cx16.r0 = 65535