* cris/traps.c (TARGET_PIPE_BUF): New macro.

	(cris_pipe_empty): Correct initialization of "remaining".  Only
	adjust the "write" return value if more than TARGET_PIPE_BUF bytes
	are written.

diff --git a/sim/ChangeLog b/sim/ChangeLog
index d68f2300ea1873b686b304004239b58cecc64f8c..bd3129ac46cfaf6a8e4d309c5f9cd51647d0cbf4 100644 (file)
--- a/sim/ChangeLog
+++ b/sim/ChangeLog
@@ -1,3 +1,10 @@
+2006-09-30  Hans-Peter Nilsson  <hp@axis.com>
+
+       * cris/traps.c (TARGET_PIPE_BUF): New macro.
+       (cris_pipe_empty): Correct initialization of "remaining".  Only
+       adjust the "write" return value if more than TARGET_PIPE_BUF bytes
+       are written.
+
 2006-09-29  Hans-Peter Nilsson  <hp@axis.com>
 
        * cris/configure.ac: Check for limits.h and sys/param.h.

diff --git a/sim/cris/traps.c b/sim/cris/traps.c
index 487fadd83a1c8018891c947e90b431bb9c955ec5..371688f70a2ad001d6dd3108f2d5a743858c659a 100644 (file)
--- a/sim/cris/traps.c
+++ b/sim/cris/traps.c
@@ -240,6 +240,9 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #define TARGET___WALL 0x40000000
 #define TARGET___WCLONE 0x80000000
 
+/* From linux/limits.h. */
+#define TARGET_PIPE_BUF 4096
+
 static const char stat_map[] =
 "st_dev,2:space,10:space,4:st_mode,4:st_nlink,4:st_uid,4"
 ":st_gid,4:st_rdev,2:space,10:st_size,8:st_blksize,4:st_blocks,4"
@@ -2971,13 +2974,14 @@ cris_pipe_nonempty (host_callback *cb ATTRIBUTE_UNUSED,
 
 static void
 cris_pipe_empty (host_callback *cb,
-                int reader ATTRIBUTE_UNUSED,
+                int reader,
                 int writer)
 {
   int i;
   SIM_CPU *cpu = current_cpu_for_cb_callback;
   bfd_byte r10_buf[4];
-  int remaining = cb->pipe_buffer[writer].size;
+  int remaining
+    = cb->pipe_buffer[writer].size - cb->pipe_buffer[reader].size;
 
   /* We need to find the thread that waits for this pipe.  */
   for (i = 0; i < SIM_TARGET_MAX_THREADS; i++)
@@ -2985,6 +2989,7 @@ cris_pipe_empty (host_callback *cb,
        && cpu->thread_data[i].pipe_write_fd == writer)
       {
        int retval;
+
        /* Temporarily switch to this cpu context, so we can change the
           PC by ordinary calls.  */
 
@@ -2995,19 +3000,25 @@ cris_pipe_empty (host_callback *cb,
                cpu->thread_data[i].cpu_context,
                cpu->thread_cpu_data_size);
 
-       /* The return value is supposed to contain the number of written
-          bytes, which is the number of bytes requested and returned at
-          the write call.  We subtract the remaining bytes from that,
-          but making sure we still get a positive number.
-          The return value may also be a negative number; an error
-          value.  We cover this case by comparing against remaining,
-          which is always >= 0.  */
+       /* The return value is supposed to contain the number of
+          written bytes, which is the number of bytes requested and
+          returned at the write call.  You might think the right
+          thing is to adjust the return-value to be only the
+          *consumed* number of bytes, but it isn't.  We're only
+          called if the pipe buffer is fully consumed or it is being
+          closed, possibly with remaining bytes.  For the latter
+          case, the writer is still supposed to see success for
+          PIPE_BUF bytes (a constant which we happen to know and is
+          unlikely to change).  The return value may also be a
+          negative number; an error value.  This case is covered
+          because "remaining" is always >= 0.  */
        (*CPU_REG_FETCH (cpu)) (cpu, H_GR_R10, r10_buf, 4);
        retval = (int) bfd_getl_signed_32 (r10_buf);
-       if (retval >= remaining)
-         bfd_putl32 (retval - remaining, r10_buf);
-       (*CPU_REG_STORE (cpu)) (cpu, H_GR_R10, r10_buf, 4);
-
+       if (retval - remaining > TARGET_PIPE_BUF)
+         {
+           bfd_putl32 (retval - remaining, r10_buf);
+           (*CPU_REG_STORE (cpu)) (cpu, H_GR_R10, r10_buf, 4);
+         }
        sim_pc_set (cpu, sim_pc_get (cpu) + 2);
        memcpy (cpu->thread_data[i].cpu_context,
                &cpu->cpu_data_placeholder,