patch-2.2.18 linux/arch/arm/nwfpe/fpmodule.c

• Lines: 186
• Date: Fri Sep 15 23:28:37 2000
• Orig file: v2.2.17/arch/arm/nwfpe/fpmodule.c
• Orig date: Thu Jan 1 01:00:00 1970

diff -u --new-file --recursive --exclude-from /usr/src/exclude v2.2.17/arch/arm/nwfpe/fpmodule.c linux/arch/arm/nwfpe/fpmodule.c
@@ -0,0 +1,185 @@
+/*
+    NetWinder Floating Point Emulator
+    (c) Corel Computer Corporation, 1998
+    (c) Philip Blundell, 1998-1999
+
+    Direct questions, comments to Scott Bambrough <scottb@corelcomputer.com>
+
+    This program 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 2 of the License, or
+    (at your option) any later version.
+
+    This program 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 this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#include "config.h"
+
+#ifdef MODULE
+#include <linux/module.h>
+#include <linux/version.h>
+#else
+#define MOD_INC_USE_COUNT
+#define MOD_DEC_USE_COUNT
+#endif
+
+/* XXX */
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+
+#include <asm/system.h>
+#include <asm/uaccess.h>
+#include <asm/io.h>
+#include <asm/spinlock.h>
+#include <asm/atomic.h>
+#include <asm/pgtable.h>
+/* XXX */
+
+#include "softfloat.h"
+#include "fpopcode.h"
+#include "fpmodule.h"
+#include "fpa11.h"
+#include "fpa11.inl"
+
+/* external data */
+extern FPA11 *fpa11;
+
+/* kernel symbols required for signal handling */
+typedef struct task_struct*	PTASK;
+
+#ifdef MODULE
+int fp_printk(const char *,...);
+void fp_send_sig(unsigned long sig, PTASK p, int priv);
+#if LINUX_VERSION_CODE > 0x20115
+MODULE_AUTHOR("Scott Bambrough <scottb@corelcomputer.com>");
+MODULE_DESCRIPTION("NWFPE floating point emulator");
+#endif
+
+#else
+#define fp_printk	printk
+#define fp_send_sig	send_sig
+#define kern_fp_enter	fp_enter
+#endif
+
+/* kernel function prototypes required */
+void C_SYMBOL_NAME(fp_setup)(void);
+
+/* external declarations for saved kernel symbols */
+extern unsigned int C_SYMBOL_NAME(kern_fp_enter);
+
+/* forward declarations */
+extern void nwfpe_enter(void);
+
+/* Original value of fp_enter from kernel before patched by fpe_init. */ 
+static unsigned int orig_fp_enter;
+
+/* Address of user registers on the kernel stack. */
+unsigned int *userRegisters;
+
+void __init C_SYMBOL_NAME(fpe_version)(void)
+{
+  static const char szTitle[] = "<4>NetWinder Floating Point Emulator ";
+  static const char szVersion[] = "V0.94.1 ";
+  static const char szCopyright[] = "(c) 1998 Corel Computer Corp.\n";
+  C_SYMBOL_NAME(fp_printk)(szTitle);
+  C_SYMBOL_NAME(fp_printk)(szVersion);
+  C_SYMBOL_NAME(fp_printk)(szCopyright);
+}
+
+int __init fpe_init(void)
+{
+  /* Display title, version and copyright information. */
+  C_SYMBOL_NAME(fpe_version)();
+
+  /* Save pointer to the old FP handler and then patch ourselves in */
+  orig_fp_enter = C_SYMBOL_NAME(kern_fp_enter);
+  C_SYMBOL_NAME(kern_fp_enter) = (unsigned int)C_SYMBOL_NAME(nwfpe_enter);
+
+  return 0;
+}
+
+#ifdef MODULE
+int init_module(void)
+{
+  return(fpe_init());
+}
+
+void cleanup_module(void)
+{
+  /* Restore the values we saved earlier. */
+  C_SYMBOL_NAME(kern_fp_enter) = orig_fp_enter;
+}
+#endif
+
+#define _ARM_pc 60
+#define _ARM_cpsr 64
+
+/*
+ScottB:  November 4, 1998
+
+Moved this function out of softfloat-specialize into fpmodule.c.
+This effectively isolates all the changes required for integrating with the
+Linux kernel into fpmodule.c.  Porting to NetBSD should only require modifying
+fpmodule.c to integrate with the NetBSD kernel (I hope!).
+
+[1/1/99: Not quite true any more unfortunately.  There is Linux-specific
+code to access data in user space in some other source files at the 
+moment.  --philb]
+
+float_exception_flags is a global variable in SoftFloat.
+
+This function is called by the SoftFloat routines to raise a floating
+point exception.  We check the trap enable byte in the FPSR, and raise
+a SIGFPE exception if necessary.  If not the relevant bits in the 
+cumulative exceptions flag byte are set and we return.
+*/
+
+void float_raise(signed char flags)
+{
+  register unsigned int fpsr, cumulativeTraps;
+  
+#if 0
+  printk(KERN_DEBUG "NWFPE: exception %08x at %08x from %08x\n", flags,
+	 __builtin_return_address(0), userRegisters[15]);
+#endif
+
+  /* Keep SoftFloat exception flags up to date.  */
+  float_exception_flags |= flags;
+
+  /* Read fpsr and initialize the cumulativeTraps.  */
+  fpsr = readFPSR();
+  cumulativeTraps = 0;
+  
+  /* For each type of exception, the cumulative trap exception bit is only
+     set if the corresponding trap enable bit is not set.  */
+  if ((!(fpsr & BIT_IXE)) && (flags & BIT_IXC))
+     cumulativeTraps |= BIT_IXC;  
+  if ((!(fpsr & BIT_UFE)) && (flags & BIT_UFC))
+     cumulativeTraps |= BIT_UFC;  
+  if ((!(fpsr & BIT_OFE)) && (flags & BIT_OFC))
+     cumulativeTraps |= BIT_OFC;  
+  if ((!(fpsr & BIT_DZE)) && (flags & BIT_DZC))
+     cumulativeTraps |= BIT_DZC;  
+  if ((!(fpsr & BIT_IOE)) && (flags & BIT_IOC))
+     cumulativeTraps |= BIT_IOC;  
+
+  /* Set the cumulative exceptions flags.  */
+  if (cumulativeTraps)
+    writeFPSR(fpsr | cumulativeTraps);
+
+  /* Raise an exception if necessary.  */
+  if (fpsr & (flags << 16))
+    fp_send_sig(SIGFPE, current, 1);
+}