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authorUlrich Drepper <drepper@redhat.com>1998-05-21 15:40:14 +0000
committerUlrich Drepper <drepper@redhat.com>1998-05-21 15:40:14 +0000
commit23f0c99c0eb54cd481167d5927dafc1650bcbca1 (patch)
treecd1db4054738b46da815bf3a258b143b20063170 /sysdeps/arm/fpu_control.h
parent32c85e43ed25cc954cb9ba62a6aad7c9338a2a08 (diff)
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Update.
1998-05-21 15:27  Ulrich Drepper  <drepper@cygnus.com>

	* wcsmbs/wcsnrtombs.c: Correct computation of result.
	* wcsmbs/wcsrtombs.c: Likewise.

	* wcsmbs/Makefile (tests): Add wcsmbs-tst1.c.
	* wcsmbs/wcsmbs-tst1.c: New file.

	* iconv/loop.c (COUNT_CONVERTED): Correct computation.

	* locale/C-ctype.c (_nl_C_LC_CTYPE): Define MB_CUR_MAX for C locale
	as 1.

	* locale/setlocale.c: Don't make _nl_current_* and _nl_C_* references
	weak.

1998-05-21  Philip Blundell  <philb@gnu.org>

	* sysdeps/arm/fpu_control.h: Replace stub file with real
	implementation.
	* sysdeps/arm/fpu/bits/fenv.h: New file.
	* sysdeps/arm/fpu/fesetround.c: Likewise.
	* sysdeps/arm/fpu/fclrexcpt.c: Likewise.
	* sysdeps/arm/fpu/fsetexcptflag.c: Likewise.
	* sysdeps/arm/fpu/ftestexcpt.c: Likewise.
	* sysdeps/arm/fpu/fraiseexcpt.c: Likewise.
	* sysdeps/arm/fpu/fegetenv.c: Likewise.
	* sysdeps/arm/fpu/fesetenv.c: Likewise.

1998-05-21 16:34  Richard Henderson  <rth@cygnus.com>

	* elf/dl-load.c (_dl_map_object_from_fd): Get file header with
	read instead of mmap.
Diffstat (limited to 'sysdeps/arm/fpu_control.h')
-rw-r--r--sysdeps/arm/fpu_control.h61
1 files changed, 53 insertions, 8 deletions
diff --git a/sysdeps/arm/fpu_control.h b/sysdeps/arm/fpu_control.h
index 054085d70a..8a2d338c49 100644
--- a/sysdeps/arm/fpu_control.h
+++ b/sysdeps/arm/fpu_control.h
@@ -1,5 +1,5 @@
-/* FPU control word definitions.  Stub version.
-   Copyright (C) 1996, 1997 Free Software Foundation, Inc.
+/* FPU control word definitions.  ARM version.
+   Copyright (C) 1996, 1997, 1998 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -20,7 +20,54 @@
 #ifndef _FPU_CONTROL_H
 #define _FPU_CONTROL_H
 
-#define _FPU_RESERVED 0xffffffff  /* These bits are reserved.  */
+/* We have a slight terminology confusion here.  On the ARM, the register
+ * we're interested in is actually the FPU status word - the FPU control
+ * word is something different (which is implementation-defined and only
+ * accessible from supervisor mode.)  
+ *
+ * The FPSR looks like this:
+ *
+ *     31-24        23-16          15-8              7-0
+ * | system ID | trap enable | system control | exception flags | 
+ *
+ * We ignore the system ID bits; for interest's sake they are:
+ *
+ *  0000	"old" FPE
+ *  1000	FPPC hardware
+ *  0001	FPE 400
+ *  1001	FPA hardware
+ *
+ * The trap enable and exception flags are both structured like this:
+ *
+ *     7 - 5     4     3     2     1     0
+ * | reserved | INX | UFL | OFL | DVZ | IVO | 
+ *
+ * where a `1' bit in the enable byte means that the trap can occur, and
+ * a `1' bit in the flags byte means the exception has occurred.
+ *
+ * The exceptions are:
+ *
+ *  IVO - invalid operation
+ *  DVZ - divide by zero
+ *  OFL - overflow
+ *  UFL - underflow
+ *  INX - inexact (do not use; implementations differ)
+ *
+ * The system control byte looks like this:
+ *
+ *     7-5      4    3    2    1    0
+ * | reserved | AC | EP | SO | NE | ND |
+ * 
+ * where the bits mean
+ *
+ *  ND - no denormalised numbers (force them all to zero)
+ *  NE - enable NaN exceptions
+ *  SO - synchronous operation
+ *  EP - use expanded packed-decimal format
+ *  AC - use alternate definition for C flag on compare operations
+ */
+
+#define _FPU_RESERVED 0xfff0e0f0  /* These bits are reserved.  */
 
 /* The fdlibm code requires no interrupts for exceptions.  Don't
    change the rounding mode, it would break long double I/O!  */
@@ -29,11 +76,9 @@
 /* Type of the control word.  */
 typedef unsigned int fpu_control_t;
 
-/* Macros for accessing the hardware control word.
- * On the ARM, we can't do this from user mode (it would trap).
- */
-#define _FPU_GETCW(cw) __asm__ ("movnv r0,r0" : "=g" (cw))
-#define _FPU_SETCW(cw) __asm__ ("movnv r0,r0" : : "g" (cw))
+/* Macros for accessing the hardware control word.  */
+#define _FPU_GETCW(cw) __asm__ ("rfs %0" : "=r" (cw))
+#define _FPU_SETCW(cw) __asm__ ("wfs %0" : : "r" (cw))
 
 /* Default control word set at startup.  */
 extern fpu_control_t __fpu_control;