[src/trunk]: src/sys/arch/sparc/include Improve _UC_MACHINE_FP() for SPARC/SP...

[kamil <kamil%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/05b06cacff44
branches:  trunk
changeset: 829915:05b06cacff44
user:      kamil <kamil%NetBSD.org@localhost>
date:      Sat Feb 17 15:22:22 2018 +0000

description:
Improve _UC_MACHINE_FP() for SPARC/SPARC64

Introduce a static inline function _uc_machine_fp() that contains improved
caluclation of a frame pointer.

Algorithm:

  uptr *stk_ptr;
#  if defined (__arch64__)
  stk_ptr = (uptr *) (*sp + 2047);
#  else
  stk_ptr = (uptr *) *sp;
#  endif
  *bp = stk_ptr[15];

Noted by <mrg>

diffstat:

 sys/arch/sparc/include/mcontext.h |  22 ++++++++++++++++++----
 1 files changed, 18 insertions(+), 4 deletions(-)

diffs (45 lines):

diff -r a6c3cf61dc6b -r 05b06cacff44 sys/arch/sparc/include/mcontext.h
--- a/sys/arch/sparc/include/mcontext.h Sat Feb 17 13:54:52 2018 +0000
+++ b/sys/arch/sparc/include/mcontext.h Sat Feb 17 15:22:22 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: mcontext.h,v 1.14 2018/02/15 15:53:57 kamil Exp $      */
+/*     $NetBSD: mcontext.h,v 1.15 2018/02/17 15:22:22 kamil Exp $      */
 
 /*-
  * Copyright (c) 2001 The NetBSD Foundation, Inc.
@@ -146,18 +146,32 @@
 #ifdef __arch64__
 #define _UC_MACHINE_PAD        8               /* Padding appended to ucontext_t */
 #define        _UC_MACHINE_SP(uc)      (((uc)->uc_mcontext.__gregs[_REG_O6])+0x7ff)
-#define        _UC_MACHINE_FP(uc)      (((uc)->uc_mcontext.__gregs[_REG_O6])+0x80e)
+#define        _UC_MACHINE_FP(uc)      (_uc_machine_fp((uc), 2047))
 #define _UC_MACHINE32_PAD      43      /* compat_netbsd32 variant */
 #define        _UC_MACHINE32_SP(uc)    ((uc)->uc_mcontext.__gregs[_REG_O6])
-#define        _UC_MACHINE32_FP(uc)    (((uc)->uc_mcontext.__gregs[_REG_O6])+0xf)
+#define        _UC_MACHINE32_FP(uc)    (_uc_machine_fp((uc), 0))
 #else
 #define _UC_MACHINE_PAD        43              /* Padding appended to ucontext_t */
 #define        _UC_MACHINE_SP(uc)      ((uc)->uc_mcontext.__gregs[_REG_O6])
-#define        _UC_MACHINE_FP(uc)      (((uc)->uc_mcontext.__gregs[_REG_O6])+0xf)
+#define        _UC_MACHINE_FP(uc)      (_uc_machine_fp((uc), 0))
 #endif
 #define        _UC_MACHINE_PC(uc)      ((uc)->uc_mcontext.__gregs[_REG_PC])
 #define        _UC_MACHINE_INTRV(uc)   ((uc)->uc_mcontext.__gregs[_REG_O0])
 
+static inline long
+_uc_machine_fp(ucontext_t *ucontext, long shift)
+{
+       long *sptr;
+       long *sp;
+       long fp;
+
+       sp = (long *)_UC_MACHINE_SP(ucontext);
+       sptr = (long *)(*sp + shift);
+       fp = sptr[15];
+
+       return fp;
+}
+
 #define        _UC_MACHINE_SET_PC(uc, pc)                                      \
 do {                                                                   \
        (uc)->uc_mcontext.__gregs[_REG_PC] = (pc);                      \