From 0d852247f1662c836ba8772909e932b08e68fd7b Mon Sep 17 00:00:00 2001
From: ggn <ggn@atari.org>
Date: Tue, 20 Dec 2022 23:48:39 +0200
Subject: [PATCH] Added support for C64 .PRG output format (#194)

---
 6502.c   | 31 +++++++++++++++++++++++++++++++
 6502.h   |  2 ++
 object.c |  5 +++++
 rmac.c   |  5 +++++
 rmac.h   |  1 +
 5 files changed, 44 insertions(+)

diff --git a/6502.c b/6502.c
index c523086..5d1d7c7 100644
--- a/6502.c
+++ b/6502.c
@@ -587,3 +587,34 @@ void m6502raw(int ofd)
 		uint32_t unused = write(ofd, p + l[0], l[1] - l[0]);
 	}
 }
+
+// 
+// Generate a C64 .PRG output file
+//
+void m6502c64(int ofd)
+{
+	uint8_t header[2];
+	uint32_t unused;
+
+	CHUNK *ch = sect[M6502].scode;
+
+	// If no 6502 code was generated, bail out
+	if ((ch == NULL) || (ch->challoc == 0))
+		return;
+
+	if (currentorg != &orgmap[1][0])
+	{
+		// More than one 6502 section created, this is not allowed
+		error("when generating C64 .PRG files only one org section is allowed - aborting");
+		return;
+	}
+	
+	SETLE16(header, 0, orgmap[0][0]);
+	register uint8_t *p = ch->chptr;
+
+	// Write header
+	unused = write(ofd, header, 2);
+	// Write the data
+	unused = write(ofd, p + orgmap[0][0], orgmap[0][1] - orgmap[0][0]);
+
+}
\ No newline at end of file
diff --git a/6502.h b/6502.h
index bddf065..453c66b 100644
--- a/6502.h
+++ b/6502.h
@@ -19,6 +19,8 @@ extern void Init6502();
 extern int d_6502();
 extern void m6502cg(int op);
 extern void m6502obj(int ofd);
+extern void m6502raw(int ofd);
+extern void m6502c64(int ofd);
 
 #endif // __6502_H__
 
diff --git a/object.c b/object.c
index 6a69fcf..6dbf9c5 100644
--- a/object.c
+++ b/object.c
@@ -831,6 +831,11 @@ for(int j=0; j<i; j++)
 		// Just write the object file
 		m6502obj(fd);
 	}
+	else if (obj_format == C64PRG)
+	{
+		// Just write the object file
+		m6502c64(fd);
+	}
 	else if (obj_format == P56 || obj_format == LOD)
 	{
 		// Allocate 6MB object file image memory
diff --git a/rmac.c b/rmac.c
index 26b1222..8e5f410 100644
--- a/rmac.c
+++ b/rmac.c
@@ -164,6 +164,7 @@ void DisplayHelp(void)
 		"  -f[format]        Output object file format\n"
 		"                    a: ALCYON\n"
 		"                    b: BSD (use this for Jaguar)\n"
+		"                    c: PRG (C64)\n"
 		"                    e: ELF\n"
 		"                    p: P56 (use this for DSP56001 only)\n"
 		"                    l: LOD (use this for DSP56001 only)\n"
@@ -445,6 +446,10 @@ int Process(int argc, char ** argv)
 				case 'B':
 					obj_format = BSD;
 					break;
+				case 'c':
+				case 'C':
+					obj_format = C64PRG;
+					break;
 				case 'e':			// -fe = ELF
 				case 'E':
 					obj_format = ELF;
diff --git a/rmac.h b/rmac.h
index 388adec..00dcd3b 100644
--- a/rmac.h
+++ b/rmac.h
@@ -198,6 +198,7 @@ LOD,				// DSP 56001 object format
 P56,				// DSP 56001 object format
 XEX, 				// COM/EXE/XEX/whatever a8 object format
 RAW,				// Output at absolute address
+C64PRG,				// C64 .PRG format
 };
 
 // Assembler token
-- 
2.38.1.windows.1