Add compile-expr/

compile-expr/.gitignore

@@ -0,0 +1,3 @@
+expr
+expr.o
+expr.s

compile-expr/Makefile

@@ -0,0 +1,8 @@
+expr: expr.o
+	ld expr.o -o expr -l System -syslibroot `xcrun -sdk macosx --show-sdk-path` -e main -arch arm64
+
+expr.o: expr.s
+	as expr.s -o expr.o
+
+expr.s: expr.ppp
+	./expr.py expr.ppp > expr.s

compile-expr/expr.ppp

@@ -0,0 +1 @@
+(((a*b)+(c*d))*((e*f)+(g*h)))+(((i*j)+(k*l))*((m*n)+(o*p)))

compile-expr/expr.py

@@ -0,0 +1,61 @@
+#!/usr/bin/env python3
+
+"""
+Generates the ARM64 Assembly for an executable that performs the given 
+calculation and exits with that number as the exit code. It currently
+only allows for multiplication and addition. You can check the output
+modulo 256 using `echo $?`. The only defined variables are the letters
+a-z, where they represent their 1-based index into the alphabet.
+"""
+
+import string
+import sys, os; sys.path.append(os.path.abspath(os.path.join(os.path.dirname(__file__), '..'))) # just becuase this is in a subdirectory
+from ppp_lexer import *
+from ppp_parser import *
+
+_program, file_path = sys.argv
+
+lexer = Lexer.from_file(file_path)
+expr = parse_expression(lexer)
+lexer.assert_token(EofToken())
+
+def get_index(char: str) -> int:
+	"""
+	Assuming char is [a-z]
+	"""
+	return ord(char)-96
+
+def get_stack_address(index: int) -> int:
+	return 112-index*4
+
+def to_asm(expr: Expression, *, taken: int=0):
+	"""
+	Generates the assembly using registers w0, w1, w2, ... as a stack.
+
+	`taken` is how many registers are already taken by previous elements 'on the stack'
+	"""
+	if isinstance(expr, Variable):
+		assert expr.name in string.ascii_lowercase
+		address = get_stack_address(get_index(expr.name))
+		print(f"\tldr w{taken}, [sp, {address}] // {expr.name}")
+	else:
+		match expr:
+			case Addition():       word = 'add'
+			case Multiplication(): word = 'mul'
+			case _: assert False, f"Unimplemented: {expr}"
+		to_asm(expr.lhs, taken=taken)
+		to_asm(expr.rhs, taken=taken+1)
+
+		print(f"\t{word} w{taken}, w{taken}, w{taken+1} // {expr.represent()}")
+
+print(".global main")
+print(".align 2")
+print()
+print("main:")
+print("\tsub sp, sp, #112") # to fit 26*4=104 bytes. It seems that the sp should only be offset by 16 bytes at a time.
+for i in range(1,27):
+	print(f"\tmov w0, {i}")
+	print(f"\tstr w0, [sp, {get_stack_address(i)}]")
+to_asm(expr)
+print("\tadd sp, sp, 112")
+print("\tret")