Issues in compiling PASC into SPARC assembly.

1

• Issues in compiling PASC into SPARC assembly.
• Predefined subroutines.
• Write them in C
• Compile them with GCC or CC
• Code generation must following the CC calling
  convention
• o0 first argument
• o1 second argument
• See lib.c and t1.s

2

• Memory allocation
• Global variables just allocation a chunk of
  memory
• Augment the symbol table to include offsets.
• You can associate the symbol with its location.
• Still need to use offset to deal with arrays and
  records.
• Accessing the variables see t2.pasc
• Local variables
• Allocate space on the stack.
• Access the variable through the frame point
  (using the offset information)

3

• Memory allocation
• Temporaries
• To simplify the compilation, we can always use
  memory to store the temporaries.
• With the reuse scheme, the number of temporaries
  would not be too many can just allocate as a
  global data
• Code generation for calculations
• SPARC only performs computations using registers.
• Can just generate a sequence of code for each
  intermediate instruction, such as t1 t2 t3
• See example t3.s

4

• Other features of sparc assembly
• Delay slot the instruction after a branch
  instruction will be executed.
• To simplify code generation, add nop to every
  branch instruction.
• save/restore the use of register files to speed
  up function calls.
• Data alignment integers must be aligned to 4
  bytes.

5

• The use of proj4.c
• See example1.c and example2.c
• It would help if you implement the generate emit
  routine.