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>
micropython · Mar 28, 2022 · 6d11c69 · 6d11c69
1 parent acd2c5c
commit 6d11c69
Show file tree

Hide file tree

Showing 5 changed files with 11 additions and 13 deletions.
diff --git 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
@@ -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
@@ -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
@@ -560,21 +560,21 @@ FRAME_SETUP();
                 }
 
                 ENTRY(MP_BC_JUMP_IF_TRUE_OR_POP): {
-                    DECODE_SLABEL;
+                    DECODE_ULABEL;
                     if (mp_obj_is_true(TOP())) {
-                        ip += slab;
+                        ip += ulab;
                     } else {
                         sp--;
                     }
                     DISPATCH_WITH_PEND_EXC_CHECK();
                 }
 
                 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();
                 }

diff --git a/tools/mpy-tool.py b/tools/mpy-tool.py
@@ -246,8 +246,8 @@ class Opcodes:
     MP_BC_JUMP                        = (MP_BC_BASE_JUMP_E + 0x02) # signed relative bytecode offset
     MP_BC_POP_JUMP_IF_TRUE            = (MP_BC_BASE_JUMP_E + 0x03) # signed relative bytecode offset
     MP_BC_POP_JUMP_IF_FALSE           = (MP_BC_BASE_JUMP_E + 0x04) # signed relative bytecode offset
-    MP_BC_JUMP_IF_TRUE_OR_POP         = (MP_BC_BASE_JUMP_E + 0x05) # signed relative bytecode offset
-    MP_BC_JUMP_IF_FALSE_OR_POP        = (MP_BC_BASE_JUMP_E + 0x06) # signed relative bytecode offset
+    MP_BC_JUMP_IF_TRUE_OR_POP         = (MP_BC_BASE_JUMP_E + 0x05) # unsigned relative bytecode offset
+    MP_BC_JUMP_IF_FALSE_OR_POP        = (MP_BC_BASE_JUMP_E + 0x06) # unsigned relative bytecode offset
     MP_BC_SETUP_WITH                  = (MP_BC_BASE_JUMP_E + 0x07) # unsigned relative bytecode offset
     MP_BC_SETUP_EXCEPT                = (MP_BC_BASE_JUMP_E + 0x08) # unsigned relative bytecode offset
     MP_BC_SETUP_FINALLY               = (MP_BC_BASE_JUMP_E + 0x09) # unsigned relative bytecode offset
@@ -295,8 +295,6 @@ class Opcodes:
         MP_BC_JUMP,
         MP_BC_POP_JUMP_IF_TRUE,
         MP_BC_POP_JUMP_IF_FALSE,
-        MP_BC_JUMP_IF_TRUE_OR_POP,
-        MP_BC_JUMP_IF_FALSE_OR_POP,
     )
 
     # Create a dict mapping opcode value to opcode name.