py: Change jump-if-x-or-pop opcodes to have unsigned offset argument.

These jumps are always forwards, and it's more efficient in the VM to
decode an unsigned argument.  These opcodes are already optimised versions
of the sequence "dup-top pop-jump-if-x pop" so it doesn't hurt generality
to optimise them further.

Signed-off-by: Damien George <damien@micropython.org>

4 files changed, 9 insertions, 9 deletions

diff --git a/py/bc0.h b/py/bc0.h
index 50c4954b0..a4a0acf93 100644
--- a/py/bc0.h
+++ b/py/bc0.h
@@ -117,8 +117,8 @@
 #define MP_BC_JUMP                          (MP_BC_BASE_JUMP_E + 0x02) // signed relative bytecode offset
 #define MP_BC_POP_JUMP_IF_TRUE              (MP_BC_BASE_JUMP_E + 0x03) // signed relative bytecode offset
 #define MP_BC_POP_JUMP_IF_FALSE             (MP_BC_BASE_JUMP_E + 0x04) // signed relative bytecode offset
-#define MP_BC_JUMP_IF_TRUE_OR_POP           (MP_BC_BASE_JUMP_E + 0x05) // signed relative bytecode offset
-#define MP_BC_JUMP_IF_FALSE_OR_POP          (MP_BC_BASE_JUMP_E + 0x06) // signed relative bytecode offset
+#define MP_BC_JUMP_IF_TRUE_OR_POP           (MP_BC_BASE_JUMP_E + 0x05) // unsigned relative bytecode offset
+#define MP_BC_JUMP_IF_FALSE_OR_POP          (MP_BC_BASE_JUMP_E + 0x06) // unsigned relative bytecode offset
 #define MP_BC_SETUP_WITH                    (MP_BC_BASE_JUMP_E + 0x07) // unsigned relative bytecode offset
 #define MP_BC_SETUP_EXCEPT                  (MP_BC_BASE_JUMP_E + 0x08) // unsigned relative bytecode offset
 #define MP_BC_SETUP_FINALLY                 (MP_BC_BASE_JUMP_E + 0x09) // unsigned relative bytecode offset
diff --git a/py/emitbc.c b/py/emitbc.c
index 90ab6c0a9..1f5cd9d32 100644
--- a/py/emitbc.c
+++ b/py/emitbc.c
@@ -224,7 +224,7 @@ STATIC void emit_write_bytecode_byte_label(emit_t *emit, int stack_adj, byte b1,
     mp_emit_bc_adjust_stack_size(emit, stack_adj);
 
     // Determine if the jump offset is signed or unsigned, based on the opcode.
-    const bool is_signed = b1 <= MP_BC_JUMP_IF_FALSE_OR_POP;
+    const bool is_signed = b1 <= MP_BC_POP_JUMP_IF_FALSE;
 
     // Default to a 2-byte encoding (the largest) with an unknown jump offset.
     unsigned int jump_encoding_size = 1;
diff --git a/py/showbc.c b/py/showbc.c
index 178fa451a..f9c334b93 100644
--- a/py/showbc.c
+++ b/py/showbc.c
@@ -338,12 +338,12 @@ const byte *mp_bytecode_print_str(const mp_print_t *print, const byte *ip_start,
             break;
 
         case MP_BC_JUMP_IF_TRUE_OR_POP:
-            DECODE_SLABEL;
+            DECODE_ULABEL;
             mp_printf(print, "JUMP_IF_TRUE_OR_POP " UINT_FMT, (mp_uint_t)(ip + unum - ip_start));
             break;
 
         case MP_BC_JUMP_IF_FALSE_OR_POP:
-            DECODE_SLABEL;
+            DECODE_ULABEL;
             mp_printf(print, "JUMP_IF_FALSE_OR_POP " UINT_FMT, (mp_uint_t)(ip + unum - ip_start));
             break;
 
diff --git a/py/vm.c b/py/vm.c
index 990009c00..50da90e7d 100644
--- a/py/vm.c
+++ b/py/vm.c
@@ -560,9 +560,9 @@ dispatch_loop:
                 }
 
                 ENTRY(MP_BC_JUMP_IF_TRUE_OR_POP): {
-                    DECODE_SLABEL;
+                    DECODE_ULABEL;
                     if (mp_obj_is_true(TOP())) {
-                        ip += slab;
+                        ip += ulab;
                     } else {
                         sp--;
                     }
@@ -570,11 +570,11 @@ dispatch_loop:
                 }
 
                 ENTRY(MP_BC_JUMP_IF_FALSE_OR_POP): {
-                    DECODE_SLABEL;
+                    DECODE_ULABEL;
                     if (mp_obj_is_true(TOP())) {
                         sp--;
                     } else {
-                        ip += slab;
+                        ip += ulab;
                     }
                     DISPATCH_WITH_PEND_EXC_CHECK();
                 }