EECS 665 - Fall 2008
Assignment 3
csem
csem reads a C program (actually a subset of C) from its standard input and compiles it into
a list of intermediate language quadruples on its standard output. The form of the quadruple
operators appear below:
x := y op z operate on yand zand place result in x
bt x lab branch to lab iff xis true
br lab branch to lab
x:= global name yield address of global identifier name
x:= local nyield address of local n
x:= param nyield address of parameter n
x:= cyield value of constant value c
x:= syield address of character string s
formal nallocate the formal having nbytes
alloc name n allocate the global name having nbytes
localloc nallocate the local having nbytes
func name begin function name
fend end function
lab=y define lab to be y
bgnstmt nbeginning of statement at line n
name denotes an identifier from the C program. ndenotes an integer. cdenotes a C integer
constant. sdenotes a string enclosed by double quotes. x,y, and zdenote quadruple temporaries.
lab denotes the location of a quadruple or a reference to a symbol defined later by a ”lab=y”
command. op denotes any of the C operators below:
== ! = <=>=
operate on xand y< > =| ∧ <<
>> +− ∗ /%
∼invert x
−negate x
@dereference x
cv convert x
fcall function ywith narguments
arg pass xas an argument
ret return x
[ ] index zinto y
followed by i(for the integer version of the operator) or by f(for the floating point version).
yis omitted for unary operators. You should assume all bitwise operators (| ∧&<<>>∼) and %
only operate on integer values.
