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branch with all branch types.

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This commit is contained in:
Kelvin Sherlock 2019-08-11 01:13:13 -04:00
parent 33ac5e0a92
commit 9b1084f9a3
1 changed files with 48 additions and 21 deletions
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69
asm.py
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@ -4,17 +4,33 @@ from time import asctime
class Block(object): class Block(object):
def __init__(self): def __init__(self):
self.size = 0 self.size = 0
self.bne = None self.branch_target = None
self.bne_long = False self.branch_long = False
self.branch_type = None
self.branch_size = 0
self.labels = [] self.labels = []
self.instr = [] self.instr = []
self.rts = False self.rts = False
self.mx = 0b11 self.mx = 0b11
def empty(self): def empty(self):
return len(self.instr) == 0 and self.bne == None return self.size + self.branch_size == 0
class Assembler(object): class Assembler(object):
__inverted_branch = {
'bne': 'beq',
'beq': 'bne',
'bvc': 'bvs',
'bvs': 'bvc',
'bpl': 'bmi',
'bmi': 'bpl',
'bcc': 'bcs',
'bcs': 'bcc'
}
def __init__(self, name): def __init__(self, name):
self.name = name self.name = name
self.blocks = [] self.blocks = []
@ -49,7 +65,9 @@ class Assembler(object):
self.blocks.append(self.b) self.blocks.append(self.b)
def bne(self, l): def bne(self, l):
self.b.bne = l self.b.branch_type = 'bne'
self.b.branch_target = l
self.b.branch_size = 2
self.new_block() self.new_block()
def emit(self, op, size): def emit(self, op, size):
@ -100,8 +118,8 @@ class Assembler(object):
b.labels = [first] b.labels = [first]
for b in self.blocks: for b in self.blocks:
if b.bne: if b.branch_target:
b.bne = map[b.bne] b.branch_target = map[b.branch_target]
def reify_branches(self): def reify_branches(self):
# in practice all branches are forward # in practice all branches are forward
@ -113,8 +131,7 @@ class Assembler(object):
for l in b.labels: for l in b.labels:
map[l] = pc map[l] = pc
pc = pc + b.size pc = pc + b.size + b.branch_size
if b.bne: pc = pc + 2 # optimist
delta = True delta = True
while delta: while delta:
@ -124,11 +141,11 @@ class Assembler(object):
for b in self.blocks: for b in self.blocks:
pc = pc + b.size pc = pc + b.size
l = b.bne l = b.branch_target
if not l: continue if not l: continue
if b.bne_long: if b.branch_long:
pc = pc + 5 pc = pc + b.branch_size
continue continue
target = map[l] target = map[l]
@ -137,25 +154,35 @@ class Assembler(object):
if diff < -128 or diff > 127: if diff < -128 or diff > 127:
delta = True delta = True
b.bne_long = True b.branch_long = True
if b.branch_type == 'bra':
b.branch_type = 'brl'
b.branch_size = 3
fudge = 1
else:
b.branch_size = 5
fudge = 3
for x in map: for x in map:
if map[x] >= pc: if map[x] >= pc:
map[x] = map[x] + 3 map[x] = map[x] + fudge
for b in self.blocks: for b in self.blocks:
l = b.bne l = b.branch_target
if not l: continue if not l: continue
if b.bne_long: t = b.branch_type
b.instr.append("\tbeq *+5")
b.instr.append("\tbrl " + l)
b.size = b.size + 5
else:
b.instr.append("\tbne " + l)
b.size = b.size + 2
if b.branch_long:
if b.branch_type not in ('bra', 'brl'):
t = self.__inverted_branch[t]
b.instr.append("\t{} *+5".format(t))
b.instr.append("\tbrl " + l)
else:
b.instr.append("\t{} {}".format(t, l))
b.size = b.size + b.branch_size
def finish(self,io): def finish(self,io):
onoff = ("on", "off") onoff = ("on", "off")