mirror of
https://git.sr.ht/~crc_/retroforth
synced 2024-11-16 19:48:56 +01:00
149 lines
3.5 KiB
Python
Executable file
149 lines
3.5 KiB
Python
Executable file
#!/usr/bin/env python3
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# retro-muri is an assembler for Nga, the virtual machine at the heart of
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# Retro. It is used to build the image file containing the actual Retro
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# language.
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#
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# This will extract the code blocks in the specified file and generate an
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# image file named `ngaImage`.
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#
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# Copyright (c) 2020, Charles Childers
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#
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# Usage:
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#
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# retro.muri.py filename
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import sys, struct
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# labels stores the label names as a dictionary, with the key being
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# the label name and the value being the location in memory.
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#
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# image stores the assembled opcodes and data.
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labels = dict()
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image = []
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# assemble() takes a string representation of an opcode bundle,
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# finds the individual opcodes, packs them into a cell-sized value,
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# and returns this value.
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#
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# Each instruction bundle has four two character instruction names,
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# with `..` used to represent a non-operation instruction.
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def assemble(inst):
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insts = [
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"..",
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"li",
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"du",
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"dr",
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"sw",
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"pu",
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"po",
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"ju",
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"ca",
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"cc",
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"re",
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"eq",
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"ne",
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"lt",
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"gt",
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"fe",
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"st",
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"ad",
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"su",
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"mu",
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"di",
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"an",
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"or",
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"xo",
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"sh",
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"zr",
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"ha",
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"ie",
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"iq",
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"ii",
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]
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a = insts.index(inst[0:2])
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b = insts.index(inst[2:4])
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c = insts.index(inst[4:6])
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d = insts.index(inst[6:8])
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o = int.from_bytes([a, b, c, d], byteorder="little", signed=False)
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return o
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# muri performs two passes. The first identifies the labels
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# and populates the `labels` dictionary
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def pass1():
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global labels
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i = 0
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f = sys.argv[1]
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in_block = False
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with open(f, "r") as source:
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for line in source.readlines():
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if line.rstrip() == "~~~":
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in_block = not in_block
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elif in_block:
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if line[0] == "i":
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i += 1
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if line[0] == "d":
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i += 1
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if line[0] == "r":
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i += 1
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if line[0] == "s":
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i += len(line[2:].rstrip()) + 1
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if line[0] == ":":
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labels[line[2:].rstrip()] = i
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# The second pass actually assembles the instructions and fills
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# the `image` array with the opcodes and data provided.
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def pass2():
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global image
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i = 0
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f = sys.argv[1]
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in_block = False
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with open(f, "r") as source:
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for line in source.readlines():
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if line.rstrip() == "~~~":
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in_block = not in_block
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elif in_block:
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if line[0] == "i":
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opcode = assemble(line[2:].rstrip())
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image[i] = opcode
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i += 1
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if line[0] == "d":
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image[i] = int(line[2:].rstrip())
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i += 1
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if line[0] == "r":
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name = line[2:].rstrip()
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image[i] = labels[name]
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i += 1
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if line[0] == "s":
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for c in line[2:].rstrip():
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image[i] = ord(c)
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i += 1
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image[i] = 0
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i += 1
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# save() handles writing the image to a file
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def save(filename):
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with open(filename, "wb") as file:
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j = 0
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while j < 1024:
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file.write(struct.pack("i", image[j]))
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j = j + 1
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if __name__ == "__main__":
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image.extend([0] * 1024)
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pass1()
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pass2()
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save("ngaImage")
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