mirror of
https://github.com/irmen/prog8.git
synced 2024-10-10 10:23:47 +00:00
65 lines
2.0 KiB
Python
65 lines
2.0 KiB
Python
"""
|
|
Programming Language for 6502/6510 microprocessors, codename 'Sick'
|
|
Shared logic for the code generators.
|
|
|
|
Written by Irmen de Jong (irmen@razorvine.net) - license: GNU GPL 3.0
|
|
"""
|
|
|
|
|
|
import math
|
|
from ..datatypes import FLOAT_MAX_POSITIVE, FLOAT_MAX_NEGATIVE
|
|
|
|
|
|
class CodeError(Exception):
|
|
pass
|
|
|
|
|
|
def to_hex(number: int) -> str:
|
|
# 0..15 -> "0".."15"
|
|
# 16..255 -> "$10".."$ff"
|
|
# 256..65536 -> "$0100".."$ffff"
|
|
assert type(number) is int
|
|
if number is None:
|
|
raise ValueError("number")
|
|
if 0 <= number < 16:
|
|
return str(number)
|
|
if 0 <= number < 0x100:
|
|
return "${:02x}".format(number)
|
|
if 0 <= number < 0x10000:
|
|
return "${:04x}".format(number)
|
|
raise OverflowError(number)
|
|
|
|
|
|
def to_mflpt5(number: float) -> bytearray:
|
|
# algorithm here https://sourceforge.net/p/acme-crossass/code-0/62/tree/trunk/ACME_Lib/cbm/mflpt.a
|
|
number = float(number)
|
|
if number < FLOAT_MAX_NEGATIVE or number > FLOAT_MAX_POSITIVE:
|
|
raise OverflowError("floating point number out of 5-byte mflpt range", number)
|
|
if number == 0.0:
|
|
return bytearray([0, 0, 0, 0, 0])
|
|
if number < 0.0:
|
|
sign = 0x80000000
|
|
number = -number
|
|
else:
|
|
sign = 0x00000000
|
|
mant, exp = math.frexp(number)
|
|
exp += 128
|
|
if exp < 1:
|
|
# underflow, use zero instead
|
|
return bytearray([0, 0, 0, 0, 0])
|
|
if exp > 255:
|
|
raise OverflowError("floating point number out of 5-byte mflpt range", number)
|
|
mant = sign | int(mant * 0x100000000) & 0x7fffffff
|
|
return bytearray([exp]) + int.to_bytes(mant, 4, "big")
|
|
|
|
|
|
def mflpt5_to_float(mflpt: bytearray) -> float:
|
|
# algorithm here https://sourceforge.net/p/acme-crossass/code-0/62/tree/trunk/ACME_Lib/cbm/mflpt.a
|
|
if mflpt == bytearray([0, 0, 0, 0, 0]):
|
|
return 0.0
|
|
exp = mflpt[0] - 128
|
|
sign = mflpt[1] & 0x80
|
|
number = 0x80000000 | int.from_bytes(mflpt[1:], "big")
|
|
number = float(number) * 2**exp / 0x100000000
|
|
return -number if sign else number
|