[PATCH] pkl: Re-implement `strace` instruction

[Mohammad-Reza Nabipoor]

2021-12-01  Mohammad-Reza Nabipoor  <mnabipoor@gnu.org>

        * libpoke/pvm.jitter (strace): Re-implement using
        `JITTER_AT_DEPTH_STACK`.
---

Hi, Jose.

The following expression will be soon replaced by
`JITTER_NUMBER_OF_ELEMENTS_STACK ()` (when Luca implements it):


 (pvm_val*)JITTER_HEIGHT_STACK () - (pvm_val*)PVM_STATE_BACKING_FIELD (canary)



Regards,
Mohammad-Reza


 ChangeLog          |  5 +++++
 libpoke/pvm.jitter | 49 +++++++++++++++++++++++-----------------------
 2 files changed, 29 insertions(+), 25 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index d0384f03..9d24b65e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2021-12-01  Mohammad-Reza Nabipoor  <mnabipoor@gnu.org>
+
+       * libpoke/pvm.jitter (strace): Re-implement using
+       `JITTER_AT_DEPTH_STACK`.
+
 2021-12-01  Jose E. Marchesi  <jemarch@gnu.org>
 
        * etc/poke.rec (1.1): Add release.
diff --git a/libpoke/pvm.jitter b/libpoke/pvm.jitter
index 6c3a1690..8c943f14 100644
--- a/libpoke/pvm.jitter
+++ b/libpoke/pvm.jitter
@@ -6087,31 +6087,30 @@ end
 instruction strace (?n)
   non-relocatable
   code
-     pvm_val tmp[1024];
-     int i = 0, j;
-     int num_elems = (int) JITTER_ARGN0;
-
-     while (((num_elems == 0 || i < num_elems)
-             && (JITTER_HEIGHT_STACK () !=
-                 PVM_STATE_BACKING_FIELD (canary))))
-        {
-          assert (i < 1024);
-          pvm_print_val_with_params (PVM_STATE_BACKING_FIELD (vm),
-                                     JITTER_TOP_STACK (),
-                                     0 /* depth */,
-                                     PVM_PRINT_FLAT,
-                                     16 /* base */,
-                                     2 /* indent */,
-                                     0 /* acutoff */,
-                                     PVM_PRINT_F_MAPS);
-          pk_puts ("\n");
-          tmp[i++] = JITTER_TOP_STACK ();
-          JITTER_DROP_STACK ();
-        }
-
-     /* Restore the stack.  */
-     for (j = (i - 1); j >= 0; j--)
-        JITTER_PUSH_STACK (tmp[j]);
+    int i = 0;
+    int num_elems_max =
+      PVM_STATE_BACKING_FIELD (canary) == NULL
+        ? 1024
+        :  (pvm_val*)JITTER_HEIGHT_STACK () -
+           (pvm_val*)PVM_STATE_BACKING_FIELD (canary);
+    int num_elems = (int) JITTER_ARGN0;
+
+    if (num_elems == 0 || num_elems > num_elems_max)
+      num_elems = num_elems_max;
+
+    while (i < num_elems)
+      {
+        pvm_print_val_with_params (PVM_STATE_BACKING_FIELD (vm),
+                                   JITTER_AT_DEPTH_STACK (i),
+                                   0 /* depth */,
+                                   PVM_PRINT_FLAT,
+                                   16 /* base */,
+                                   2 /* indent */,
+                                   0 /* acutoff */,
+                                   PVM_PRINT_F_MAPS);
+        pk_puts ("\n");
+        i++;
+      }
   end
 end
 
-- 
2.34.1