Amiga: add experimental stack swap support.

CREDITS

@@ -60,6 +60,12 @@ The Authors
 - Thomas Pfaff <tpfaff@tp76.info>
   * OpenBSD sndio driver
 
+- Alfonso Ranieri, codesets.library Open Source Team
+  * Amiga StackSwap assembly routine
+
+- Alice Rowan <petrifiedrowan@gmail.com>
+  * Various features, sound driver enhancements and fixes
+
 - Johan Samuelsson <spot@triad.se>
   * Amiga port and fixes
 

Changelog

@@ -8,6 +8,10 @@ Stable versions
 	  sndio, WinMM, AIFF, file, WAV.
 	- Use XMP_MAX_SRATE as the limit for -f instead of 48000
 	  (requires libxmp 4.7.0+).
+	- Amiga: automatically expand stack via stack cookie (OS 4),
+	  NewStackSwap (AROS), or StackSwap (Workbench 2.04+). The
+	  Workbench and AROS behavior can be disabled by defining
+	  XMP_NO_STACKSWAP.
 	- Report pan value "---" for instruments/samples without
 	  a default panning value (sub->pan < 0).
 	- Don't unmute muted IT channels unless explicitly unmuted by

src/Makefile.am

@@ -8,8 +8,9 @@ bin_PROGRAMS = xmp
 
 xmp_SOURCES = \
 	commands.c common.h delay.c getopt_long.h getopt_long.c info.c \
-	main.c options.c read_config.c sound.c sound.h sound_file.c sound_null.c \
-	sound_wav.c sound_aiff.c terminal.c util.c xmp_version.h
+	main.c main_amiga.h options.c read_config.c sound.c sound.h \
+	sound_aiff.c sound_file.c sound_null.c sound_wav.c terminal.c util.c \
+	xmp_version.h
 xmp_LDADD   = ${LIBXMP_LIBS}
 xmp_LDFLAGS = ${XMP_DARWIN_LDFLAGS}
 

src/main.c

@@ -20,6 +20,7 @@
 #if defined(XMP_AMIGA)
 #include <proto/timer.h>
 #include <time.h>
+#include "main_amiga.h"
 #endif
 #if defined(__WATCOMC__)
 #include <time.h>

src/main_amiga.h

@@ -0,0 +1,183 @@
+/***************************************************************************
+
+ codesets.library - Amiga shared library for handling different codesets
+ Copyright (C) 2001-2005 by Alfonso [alfie] Ranieri <alforan@tin.it>.
+ Copyright (C) 2005-2021 codesets.library Open Source Team
+
+ Extended Module Player modifications:
+ Copyright (C) 2026 Lachesis <petrifiedrowan@gmail.com>
+
+ This library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ This library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ Lesser General Public License for more details.
+
+ codesets.library project: http://sourceforge.net/projects/codesetslib/
+
+***************************************************************************/
+
+/* Workbench, AmigaOS, AROS, MorphOS require manually setting the
+ * size of the stack. Include in main.c and nowhere else.
+ * Partially based on libinit.c code from codesets.library.
+ *
+ * Define XMP_NO_STACKSWAP to disable StackSwap/NewStackSwap/NewPPCStackSwap.
+ */
+#ifndef XMP_MAIN_AMIGA_H
+#define XMP_MAIN_AMIGA_H
+
+#include "common.h"
+
+#if defined(XMP_AMIGA)
+
+#include <proto/exec.h>
+
+#if defined(__GNUC__) && (__GNUC__ >= 4 || (__GNUC__ >= 3 && __GNUC_MINOR__ >= 1))
+#define XMP_USED __attribute__((used))
+#else
+#define XMP_USED
+#endif
+
+#define MIN_STACK_SIZE 32768
+
+/* AmigaOS 3.2, 4.x */
+extern const char stack_cookie[];
+const char XMP_USED stack_cookie[] = "$STACK: 32768";
+
+/* libnix, when swapstack.o is included (must be located manually...). */
+extern int __stack;
+int XMP_USED __stack = MIN_STACK_SIZE;
+
+/* Workbench 2.04 through 3.1: manually set stack size via StackSwap.
+ * This needs to be performed through inline ASM to be safe.
+ *
+ * AROS: use NewStackSwap instead.
+ * MorphOS: use NewPPCStackSwap instead.
+ */
+#if !defined(__amigaos4__) && !defined(XMP_NO_STACKSWAP)
+
+int real_main(int argc, char **argv);
+
+/* The inline ASM from codesets.library expects one function argument, so
+ * it's easier to just use its semantics for now instead of rewriting it. */
+struct main_args
+{
+	int argc;
+	char **argv;
+};
+
+static ULONG main_wrapper(struct main_args *args)
+{
+	return (ULONG)real_main(args->argc, args->argv);
+}
+
+#if defined(__mc68000__) && !defined(__AROS__)
+
+ULONG xmp_stackswap_call(struct StackSwapStruct *stack,
+			ULONG (*main_fn)(struct main_args *args),
+			struct main_args *args);
+
+asm("	.text				\n\
+	.even				\n\
+	.globl _xmp_stackswap_call	\n\
+_xmp_stackswap_call:			\n\
+	moveml #0x3022,sp@-		\n\
+	movel sp@(20),d3		\n\
+	movel sp@(24),a2		\n\
+	movel sp@(28),d2		\n\
+	movel _SysBase,a6		\n\
+	movel d3,a0			\n\
+	jsr a6@(-732:W)			\n\
+	movel d2,sp@-			\n\
+	jbsr a2@			\n\
+	movel d0,d2			\n\
+	addql #4,sp			\n\
+	movel _SysBase,a6		\n\
+	movel d3,a0			\n\
+	jsr a6@(-732:W)			\n\
+	movel d2,d0			\n\
+	moveml sp@+,#0x440c		\n\
+	rts"
+);
+
+#elif defined(__AROS__)
+
+static ULONG xmp_stackswap_call(struct StackSwapStruct *stack,
+				ULONG (*main_fn)(struct main_args *args),
+				struct main_args *args)
+{
+	struct StackSwapArgs sa;
+
+	sa.Args[0] = (IPTR)args;
+
+	return NewStackSwap(stack, main_fn, &sa);
+}
+
+#elif defined(__MORPHOS__)
+
+static ULONG xmp_stackswap_call(struct StackSwapStruct *stack,
+				ULONG (*main_fn)(struct main_args *args),
+				struct main_args *args)
+{
+	struct PPCStackSwapArgs sa;
+
+	sa.Args[0] = (IPTR)args;
+
+	return NewPPCStackSwap(stack, main_fn, &sa);
+}
+
+#else
+#error Unknown Amiga OS variant
+#endif
+
+int main(int argc, char **argv)
+{
+	struct StackSwapStruct sw;
+	struct Task *tc;
+	ULONG sz;
+
+	tc = FindTask(NULL);
+
+#ifdef __MORPHOS__
+	NewGetTaskAttrsA(tc, &sz, sizeof(ULONG), TASKINFOTYPE_STACKSIZE, NULL);
+#else
+	sz = (UBYTE *)tc->tc_SPUpper - (UBYTE *)tc->tc_SPLower;
+#endif
+
+	if (sz < MIN_STACK_SIZE) {
+		sw.stk_Lower = AllocVec(MIN_STACK_SIZE, MEMF_PUBLIC);
+		if (sw.stk_Lower != NULL) {
+			struct main_args args;
+			int ret;
+
+			sw.stk_Upper = (ULONG)sw.stk_Lower + MIN_STACK_SIZE;
+			sw.stk_Pointer = (APTR)sw.stk_Upper;
+
+			/*
+			printf("Swapping stack to size %d...\n", MIN_STACK_SIZE);
+			fflush(stdout);
+			*/
+
+			args.argc = argc;
+			args.argv = argv;
+			ret = (int)xmp_stackswap_call(&sw, main_wrapper, &args);
+
+			FreeVec(sw.stk_Lower);
+			return ret;
+		}
+	}
+
+	return real_main(argc, argv);
+}
+
+#define main real_main
+
+#endif /* !AmigaOS4 && !defined(XMP_NO_STACKSWAP) */
+
+#endif /* XMP_AMIGA */
+
+#endif /* XMP_MAIN_AMIGA_H */