* config/pa/tm-hppa.h (PSW_*): Define processor status word masks.

	(INSTRUCTION_NULLIFIED): Allow specific targets to override.
	* config/pa/tm-hppao.h (INSTRUCTION_NULLIFIED): Define to work
	around losing mach kernel behavior.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index e72ec9d1806cca7bc416be5390b152d22a5c7c3a..d2e073e8f64f51c2ac30f3fa1ae37bef184e8b46 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,10 @@
+Tue Jun 20 22:17:44 1995  Jeff Law  (law@snake.cs.utah.edu)
+
+       * config/pa/tm-hppa.h (PSW_*): Define processor status word masks.
+       (INSTRUCTION_NULLIFIED): Allow specific targets to override.
+       * config/pa/tm-hppao.h (INSTRUCTION_NULLIFIED): Define to work
+       around losing mach kernel behavior.
+
 Tue Jun 20 12:03:36 1995  Stan Shebs  <shebs@andros.cygnus.com>
 
        * monitor.c (monitor_wait): Don't use the watchdog timeout

diff --git a/gdb/config/pa/tm-hppao.h b/gdb/config/pa/tm-hppao.h
index aab7274276edd4fe3f3e74601f6d98ea133c60dc..7df4247474469979ef0ebb1a6e448637fb980740 100644 (file)
--- a/gdb/config/pa/tm-hppao.h
+++ b/gdb/config/pa/tm-hppao.h
@@ -69,5 +69,28 @@
 /* OSF1 does not need the pc space queue restored.  */
 #define NO_PC_SPACE_QUEUE_RESTORE
 
+/* The mach kernel uses the recovery counter to implement single
+   stepping.  While this greatly simplifies the kernel support
+   necessary for single stepping, it unfortunately does the wrong
+   thing in the presense of a nullified instruction (gives control
+   back two insns after the nullifed insn).  This is an artifact
+   of the HP architecture (recovery counter doesn't tick for
+   nullified insns).
+
+   Do our best to avoid losing in such situations.  */
+#define INSTRUCTION_NULLIFIED \
+(({ \
+    int ipsw = (int)read_register(IPSW_REGNUM); \
+    if (ipsw & PSW_N)  \
+      { \
+        int pcoqt = (int)read_register(PCOQ_TAIL_REGNUM); \
+        write_register(PCOQ_HEAD_REGNUM, pcoqt); \
+        write_register(PCOQ_TAIL_REGNUM, pcoqt + 0x4); \
+        write_register(IPSW_REGNUM, ipsw & ~(PSW_N | PSW_B | PSW_X)); \
+        stop_pc = pcoqt; \
+      } \
+   }), 0) 
+
 /* It's mostly just the common stuff.  */
+
 #include "pa/tm-hppa.h"