Jump optimization

Enhances jump / jr / call optimization whenever possible.

JP A
...
A:
JP B

translates JP A to JP B

Author: boriel

arch/zx48k/optimizer/__init__.py

@@ -217,7 +217,7 @@ def optimize(initial_memory):
             continue
 
         # The instruction that starts this block must be one of jr / jp
-        first = block.get_first_non_label_instruction()
+        first = block.get_next_exec_instruction()
         if first is None or first.inst not in ('jp', 'jr'):
             continue
 

arch/zx48k/optimizer/basicblock.py

@@ -495,12 +495,29 @@ def get_first_non_label_instruction(self):
         """ Returns the memcell of the given block, which is
         not a LABEL.
         """
-        for i in range(len(self)):
-            if not self.mem[i].is_label:
-                return self.mem[i]
+        for mem in self:
+            if not mem.is_label:
+                return mem
 
         return None
 
+    def get_next_exec_instruction(self):
+        """ Return the first non label instruction to be executed, either
+        in this block or in the following one. If there are more than one, return None.
+        Also returns None if there is no instruction to be executed.
+        """
+        result = self.get_first_non_label_instruction()
+        blk = self
+
+        while result is None:
+            if len(blk.goes_to) != 1:
+                return None
+
+            blk = blk.goes_to[0]
+            result = blk.get_first_non_label_instruction()
+
+        return result
+
     def guesses_initial_state_from_origin_blocks(self):
         """ Returns two dictionaries (regs, memory) that contains the common values
         of the cpustates of all comes_from blocks

tests/functional/opt3_tolosob.asm

@@ -0,0 +1,89 @@
+	org 32768
+__START_PROGRAM:
+	di
+	push ix
+	push iy
+	exx
+	push hl
+	exx
+	ld hl, 0
+	add hl, sp
+	ld (__CALL_BACK__), hl
+	ei
+__LABEL__inicio:
+	ld de, 0
+	ld hl, (_toloTimer)
+	or a
+	sbc hl, de
+	jp nz, __LABEL__inicio
+	ld a, 1
+	ld (_sobando), a
+	sub 2
+	jp nz, __LABEL3
+	ld hl, (_toloTimer)
+	inc hl
+	ld a, (hl)
+	sub 12
+	jp nz, __LABEL5
+	ld a, 3
+	ld (_sobando), a
+	jp __LABEL__inicio
+__LABEL5:
+__LABEL3:
+	ld a, (_sobando)
+	or a
+	jp nz, __LABEL__inicio
+	ld de, 10
+	ld hl, (_toloTimer)
+	or a
+	sbc hl, de
+	jp nz, __LABEL__inicio
+	ld hl, (_toloStatus)
+	ld a, (hl)
+	and 2
+	jp nz, __LABEL__inicio
+	ld a, 1
+	ld (_sobando), a
+__LABEL__pontolosobando:
+__LABEL11:
+__LABEL9:
+__LABEL7:
+__LABEL1:
+	jp __LABEL__inicio
+__END_PROGRAM:
+	di
+	ld hl, (__CALL_BACK__)
+	ld sp, hl
+	exx
+	pop hl
+	pop iy
+	pop ix
+	exx
+	ei
+	ret
+__CALL_BACK__:
+	DEFW 0
+#line 1 "eq16.asm"
+
+__EQ16:	; Test if 16bit values HL == DE
+		; Returns result in A: 0 = False, FF = True
+			xor a	; Reset carry flag
+			sbc hl, de
+			ret nz
+			inc a
+			ret
+
+#line 55 "opt3_tolosob.bas"
+
+ZXBASIC_USER_DATA:
+_toloTimer:
+	DEFB 00, 00
+_toloStatus:
+	DEFB 00, 00
+_sobando:
+	DEFB 00
+	; Defines DATA END --> HEAP size is 0
+ZXBASIC_USER_DATA_END EQU ZXBASIC_MEM_HEAP
+	; Defines USER DATA Length in bytes
+ZXBASIC_USER_DATA_LEN EQU ZXBASIC_USER_DATA_END - ZXBASIC_USER_DATA
+	END

tests/functional/opt3_tolosob.bas

@@ -0,0 +1,26 @@
+DIM toloTimer as UInteger
+DIM toloStatus as UInteger
+DIM toloLongSec, toloNSec, toloDelayAnim as UInteger
+DIM sobando as UByte
+	
+inicio:
+		if toloTimer=0 then
+                        sobando = 1
+			if sobando=2 then
+				if peek (toloTimer+1)=12 then
+					sobando=3
+					goto pontolosobando
+				end if
+			end if
+		
+			if sobando=0 then
+				if toloTimer=10 then
+					if peek(toloStatus) band %00000010=0 then
+						sobando=1
+pontolosobando:
+					end if
+				end if	
+			end if	
+		end if
+goto inicio
+