Fix offset for saving registers

gcc/config.gcc

@@ -1764,7 +1764,7 @@ epiphany-*-elf | epiphany-*-rtems*)
 	extra_headers="epiphany_intrinsics.h"
 	;;
 *-fcx-*)
-	tm_file="${tm_file} elfos.h gnu-user.h freebsd-spec.h newlib-stdint.h rs6000/sysv4.h rs6000/eabi.h rs6000/eabialtivec.h"
+	tm_file="${tm_file} elfos.h gnu-user.h freebsd-spec.h newlib-stdint.h rs6000/sysv4.h rs6000/eabi.h rs6000/eabialtivec.h rs6000/xenon.h"
 	extra_options="${extra_options} rs6000/sysv4.opt"
 	tmake_file="rs6000/t-fprules rs6000/t-ppcendian rs6000/t-ppccomm"
 	use_gcc_stdint=wrap

gcc/config/rs6000/rs6000-logue.cc

@@ -826,14 +826,11 @@ rs6000_stack_info (void)
       info->lr_save_offset = 2*reg_size;
       break;
 
-    case ABI_V4:
-      info->fp_save_offset = -info->fp_size;
-      info->gp_save_offset = info->fp_save_offset - info->gp_size;
-      info->cr_save_offset = info->gp_save_offset - info->cr_size;
-
-      if (TARGET_ALTIVEC_ABI)
-	{
-	  info->vrsave_save_offset = info->cr_save_offset - info->vrsave_size;
+    case ABI_V4: /* Just replacing the SV4 ABI with the Xenon one... It's hacky, but I was having trouble defining a special ABI_XENON */
+      info->cr_save_p = 0; /* We don't seem to save condition registers on 360 */
+      info->gp_save_offset = -0xC - info->gp_size;
+      info->fp_save_offset = info->gp_save_offset - info->fp_size;
+      info->vrsave_save_offset = info->fp_save_offset - info->vrsave_size;
 
 	  	/* Align stack so vector save area is on a quadword boundary.  */
 	  	if (info->altivec_size != 0)
@@ -845,15 +842,13 @@ rs6000_stack_info (void)
 
 			/* Adjust for AltiVec case.  */
 	  	info->ehrd_offset = info->altivec_save_offset;
-	}
-      else
-	info->ehrd_offset = info->cr_save_offset;
 
 			info->ehrd_offset -= ehrd_size;
-      info->lr_save_offset = reg_size;
+    	info->lr_save_offset = -0x8;
+    	break;
     }
 
-  save_align = (TARGET_ALTIVEC_ABI || DEFAULT_ABI == ABI_DARWIN) ? 16 : 8;
+  save_align = ((TARGET_ALTIVEC_ABI || DEFAULT_ABI == ABI_DARWIN) && DEFAULT_ABI != ABI_V4) ? 16 : 8;
   info->save_size = RS6000_ALIGN (info->fp_size
 				  + info->gp_size
 				  + info->altivec_size
@@ -947,7 +942,7 @@ debug_stack_info (rs6000_stack_t *info)
     case ABI_AIX:	 abi_string = "AIX";		break;
     case ABI_ELFv2:	 abi_string = "ELFv2";		break;
     case ABI_DARWIN:	 abi_string = "Darwin";		break;
-    case ABI_V4:	 abi_string = "V.4";		break;
+    case ABI_V4:	 abi_string = "Xenon";		break;
     }
 
   fprintf (stderr, "\tABI                 = %5s\n", abi_string);

gcc/config/rs6000/xenon.h

@@ -0,0 +1,49 @@
+/* Redefinitions for FreeChainXenon
+   Copyright (C) 2025 Aiden Isik
+
+   This file is part of GCC.
+
+   GCC is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published
+   by the Free Software Foundation; either version 3, or (at your
+   option) any later version.
+
+   GCC 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 General Public
+   License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with GCC; see the file COPYING3.  If not see
+   <http://www.gnu.org/licenses/>.  */
+
+#undef TARGET_DEBUG_STACK
+#define TARGET_DEBUG_STACK 1
+
+/* Force the pointer size to 32 bits (even though we run in 64-bit mode) */
+//#undef POINTER_SIZE
+//#define POINTER_SIZE 32
+
+/* Change the fixed area for the 360's stack frame convention */
+#undef RS6000_SAVE_AREA
+#define RS6000_SAVE_AREA 0x10 + (RS6000_ALIGN (crtl->outgoing_args_size.to_constant (), 16) - crtl->outgoing_args_size.to_constant ()) + 0x40
+
+/* Redefine the starting frame offset, since it relies on the size of the fixed area */
+#undef RS6000_STARTING_FRAME_OFFSET
+#define RS6000_STARTING_FRAME_OFFSET \
+    (cfun->calls_alloca \
+        ? (RS6000_ALIGN (crtl->outgoing_args_size + RS6000_SAVE_AREA, 16)) \
+        : (RS6000_ALIGN (crtl->outgoing_args_size, 16) + RS6000_SAVE_AREA))
+
+/* Redefine the offset of the first stack argument, since it relies on the size of the fixed area */
+#undef FIRST_PARM_OFFSET
+#define FIRST_PARM_OFFSET(FNDECL) RS6000_SAVE_AREA
+
+/* Redefine stack pointer offset, since it relies on the size of the fixed area */
+#undef STACK_POINTER_OFFSET
+#define STACK_POINTER_OFFSET RS6000_SAVE_AREA
+
+/* Redefine the offset from the stack pointer to items allocated by alloca() and friends */
+#undef STACK_DYNAMIC_OFFSET
+#define STACK_DYNAMIC_OFFSET(FUNDECL) \
+    RS6000_ALIGN (crtl->outgoing_args_size.to_constant () + STACK_POINTER_OFFSET, 16)