added floating point constants generator

Makefile

@@ -44,7 +44,7 @@ SRC_TOOLS  = $(wildcard src/tools/*.c,src/tools/*.cc)
 
 # Generated files
 
-GEN_BASIC  = build/,generated/packed_messages.s
+GEN_BASIC  = build/,generated/packed_messages.s build/,generated/float_constants.s
 GEN_KERNAL =
 
 # List of build directories
@@ -70,13 +70,14 @@ DEP_KERNAL = $(SRC_KERNAL) $(SRCDIR_KERNAL) $(GEN_KERNAL)
 
 # List of tools
 
-TOOL_COLLECT_DATA   = build/tools/collect_data
+TOOL_COLLECT_DATA       = build/tools/collect_data
-TOOL_COMPRESS_TEXT  = build/tools/compress_text
+TOOL_COMPRESS_TEXT      = build/tools/compress_text
-TOOL_PNGPREPARE     = build/tools/pngprepare
+TOOL_GENERATE_CONSTANTS = build/tools/generate_constants
-TOOL_BUILD_SEGMENT  = build/tools/build_segment
+TOOL_PNGPREPARE         = build/tools/pngprepare
-TOOL_RELEASE        = build/tools/release
+TOOL_BUILD_SEGMENT      = build/tools/build_segment
-TOOL_SIMILARITY     = build/tools/similarity
+TOOL_RELEASE            = build/tools/release
-TOOL_ASSEMBLER      = assembler/KickAss.jar
+TOOL_SIMILARITY         = build/tools/similarity
+TOOL_ASSEMBLER          = assembler/KickAss.jar
 
 TOOLS_LIST = $(pathsubst src/tools/%,build/tools/%,$(basename $(SRC_TOOLS)))
 
@@ -212,6 +213,10 @@ build/,generated/packed_messages.s: $(TOOL_COMPRESS_TEXT)
 	@mkdir -p build/,generated
 	$(TOOL_COMPRESS_TEXT) > build/,generated/packed_messages.s
 
+build/,generated/float_constants.s: $(TOOL_GENERATE_CONSTANTS)
+	@mkdir -p build/,generated
+	$(TOOL_GENERATE_CONSTANTS) -o build/,generated/float_constants.s
+
 .PRECIOUS: build/target_%/OUTB_X.BIN build/target_%/BASIC_combined.vs
 build/target_%/OUTB_X.BIN build/target_%/BASIC_combined.vs:
 	@mkdir -p build/target_$*

src/generate_constants.cc

@@ -0,0 +1,222 @@
+//
+// Utility to generate various floating points constants
+// in a Commodore-specific variable format
+//
+
+#include "common.h"
+
+#include <unistd.h>
+
+#include <cmath>
+#include <cstdio>
+#include <fstream>
+#include <iomanip>
+#include <vector>
+
+//
+// Basic types definition
+//
+
+typedef struct ConstEntry
+{
+	ConstEntry(const std::string &constName, double constValue) :
+		constName(constName),
+		constValue(constValue),
+		outString(".error \"not generated\"")
+	{
+	};
+
+	const std::string constName;
+	const double      constValue;
+
+	std::string       outString;
+
+} ConstEntry;
+
+//
+// Constants to output
+//
+
+std::vector<ConstEntry> GLOBAL_constants =
+{
+	ConstEntry(   "PI", M_PI ),
+	ConstEntry( "HALF",  0.5 ),
+	ConstEntry(    "1",  1.0 ),
+	ConstEntry(   "10", 10.0 ),
+};
+
+//
+// Command line settings
+//
+
+std::string CMD_outFile = "out.s";
+
+//
+// Common helper functions
+//
+
+void printUsage()
+{
+    std::cout << "\n" <<
+        "usage: generate_constants [-o <out file>]" << "\n\n";
+}
+
+void printBanner()
+{
+    printBannerLineTop();
+    std::cout << "// Generating floating point constants" << "\n";
+    printBannerLineBottom();
+}
+
+//
+// Top-level functions
+//
+
+void parseCommandLine(int argc, char **argv)
+{
+    int opt;
+
+    // Retrieve command line options
+
+    while ((opt = getopt(argc, argv, "o:")) != -1)
+    {
+        switch(opt)
+        {
+            case 'o': CMD_outFile   = optarg; break;
+            default: printUsage(); ERROR();
+        }
+    }
+}
+
+//
+// Constants generation
+//
+
+std::string toAssemblerString(const std::string &constName, double constValue)
+{
+	uint8_t outFloat[5] = { 0 };
+
+	// Retrieve mantissa nad exponent
+
+	int    exponent = -0x80;
+	double mantissa = frexp(std::abs(constValue), &exponent);
+	
+	// Add a bias to exponent
+
+	exponent += 0x80;
+
+	// Check if output format can contain such a number
+
+	if (exponent > 0xFF)
+	{
+		ERROR(std::string("const '")  + constName + "' abs value too large");
+	}
+	else if (exponent <= 0)
+	{
+		ERROR(std::string("const '")  + constName + "' abs value too small");
+	}
+
+	// Set output constant exponent
+
+	outFloat[0] = exponent;
+
+	// Set output constant mantissa
+
+	for (uint8_t idxByte = 1; idxByte <= 4; idxByte++)
+	{
+		for (uint8_t idxBit = 0; idxBit <= 7; idxBit++)
+		{
+			outFloat[idxByte] = outFloat[idxByte] << 1;
+			if (mantissa >= 0.5)
+			{
+				outFloat[idxByte]++;
+				mantissa -= 0.5;
+			}
+
+			mantissa *= 2;
+		}
+	}
+
+	if (outFloat[1] < 0x80) ERROR(std::string("const '")  + constName + "' not normalized");
+
+	// Set output constant sign
+
+	if (constValue >= 0.0)
+	{
+		outFloat[1] = outFloat[1] & 0x7F;
+	}
+
+	// Return the output constant as string for assembler
+
+	char buf[256] = { 0 };
+	snprintf(buf, sizeof(buf), "$%02X, $%02X, $%02X, $%02X, $%02X    // %22.10f",
+		outFloat[0],
+		outFloat[1],
+		outFloat[2],
+		outFloat[3],
+		outFloat[4],
+		constValue);
+
+	std::string outDef = std::string("\n.macro putConst_") + constName + "()\n{\n\t.byte " + buf + "\n}\n";
+
+	return outDef;
+} 
+
+
+void writeConstants()
+{
+	// Convert constants to assembler strings
+
+	for (auto &entry : GLOBAL_constants)
+	{
+		entry.outString = toAssemblerString(entry.constName, entry.constValue);
+	}
+
+    // Remove old file
+
+    unlink(CMD_outFile.c_str());
+
+    // Open output file for writing
+
+    std::ofstream outFile(CMD_outFile, std::fstream::out | std::fstream::trunc);
+    if (!outFile.good()) ERROR(std::string("can't open oputput file '") + CMD_outFile + "'");
+
+    // Write header
+
+    outFile << "//\n// Generated file - do not edit\n//\n\n";
+
+    // Write constants
+
+	for (auto &entry : GLOBAL_constants)
+	{
+		outFile << entry.outString;
+	}
+
+    if (!outFile.good())
+    {
+    	outFile.close();
+    	unlink(CMD_outFile.c_str());
+    	ERROR(std::string("can't write oputput file '") + CMD_outFile + "'");
+    }
+
+    // Close the file
+   
+    outFile.close();
+
+    std::cout << std::string("Constants written to: ") + CMD_outFile + "\n\n";
+}
+
+
+//
+// Main function
+//
+
+int main(int argc, char **argv)
+{
+    parseCommandLine(argc, argv);
+
+    printBanner();
+    writeConstants();
+
+    return 0;
+}