Add optimizer template 103 and FLAGVAL

Remove redundant XOR A instructions when the
value of A register is already 0.

Also adds new optimizer primitive FLAGVAL

Author: boriel

arch/zx48k/optimizer/basicblock.py

@@ -555,6 +555,10 @@ def optimize(self, patterns_list):
         code = self.code
         old_unary = dict(evaluator.Evaluator.UNARY)
         evaluator.Evaluator.UNARY['GVAL'] = lambda x: self.cpu.get(x)
+        evaluator.Evaluator.UNARY['FLAGVAL'] = lambda x: {
+            'c': str(self.cpu.C) if self.cpu.C is not None else helpers.new_tmp_val(),
+            'z': str(self.cpu.Z) if self.cpu.Z is not None else helpers.new_tmp_val()
+        }.get(x.lower(), helpers.new_tmp_val())
 
         if api.config.OPTIONS.optimization.value > 3:
             regs, mems = self.guesses_initial_state_from_origin_blocks()

arch/zx48k/peephole/evaluator.py

@@ -54,7 +54,8 @@
     'GVAL': lambda x: helpers.new_tmp_val(),  # To be updated in the O3 optimizer
     'IS_REQUIRED': lambda x: True,  # by default always required
     'CTEST': lambda x: memcell.MemCell(x, 1).condition_flag,  # condition test, if any. E.g. retz returns 'z'
-    'NEEDS': lambda x: memcell.MemCell(x[0], 1).needs(x[1])
+    'NEEDS': lambda x: memcell.MemCell(x[0], 1).needs(x[1]),
+    'FLAGVAL': lambda x: helpers.new_tmp_val()
 }
 
 # Binary operators

arch/zx48k/peephole/opts/103_o3_xor_a.opt

@@ -0,0 +1,15 @@
+;; Removes useless XOR a
+
+OLEVEL: 3
+OFLAG: 103
+
+REPLACE {{
+  xor a
+}}
+
+IF {{
+  (GVAL(a) == 0) && ((FLAGVAL(c) == 0 && FLAGVAL(z) == 1) || !IS_REQUIRED(f))
+}}
+
+WITH {{
+}}

tests/functional/opt3_xorxor.asm

@@ -0,0 +1,46 @@
+	org 32768
+__START_PROGRAM:
+	di
+	push ix
+	push iy
+	exx
+	push hl
+	exx
+	ld hl, 0
+	add hl, sp
+	ld (__CALL_BACK__), hl
+	ei
+__LABEL0:
+__LABEL__looproom:
+	xor a
+	ld (_push), a
+	ld (_suck), a
+	ld a, 4
+	ld (_paso), a
+	jp __LABEL0
+__END_PROGRAM:
+	di
+	ld hl, (__CALL_BACK__)
+	ld sp, hl
+	exx
+	pop hl
+	pop iy
+	pop ix
+	exx
+	ei
+	ret
+__CALL_BACK__:
+	DEFW 0
+
+ZXBASIC_USER_DATA:
+_push:
+	DEFB 00
+_suck:
+	DEFB 00
+_paso:
+	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_xorxor.bas

@@ -0,0 +1,14 @@
+do
+
+ looproom:
+       
+         push=0
+         suck=0
+         paso=4
+ 
+loop
+
+push=suck
+suck=paso
+push=push
+