CS 412/413
Introduction to Compilers
Spring 2002

Supporting Material for Code Generation Assignment

Library functions

• Interface file "io.ii" for io library functions and file "conv.ii" for conversion library functions 
• Description of library functions used in IR generation:
  
  // Dynamically allocates size bytes on the heap, consisting of
// a number of elements of elemsize bytes each. The function stores 
// the number of allocated elements and returns the address of the 
// allocated block.
function _allocate: (int size, int elemsize) -> address

// Concatenates s1 and s2 and returns result string
function _stringcat: (string s1, string s2) -> string

// Compare string s1, s2; return value is 0 if s1 == s2, 
// positive if s1 > s2, negative if s1 < s2
function _stringcompare: (string s1, string s2) -> int


• Additional abort library function, useful for the translation of array bounds checks and null pointer checks
  
  // Print message m, then abort program execution
function _icabort: (string m) 


Example programs

• Hello world: hello.ic, hello.s
• Function call: call.ic, call.s
• Fibonacci computation: fib.ic, fib.s
• String example: string.ic, string.s


Calling convention

• Function arguments pushed on stack in reverse order
• Return value stored in eax register (not on stack)
• Caller-saved registers: eax, ecx, edx
• Callee-saved registers: ebx, esi, edi, ebp, esp
  

Pentium Instruction Set Architecture

• A quick description of the Pentium Instruction Set (taken from the nasm assembler documentation)
  
  
• Complete documentation: Intel Manuals page, which includes:
• Intel Architecture Optimizations Manual
• Intel Architecture Software Developer's Manual, Volume 1: Basic Architecture
• Intel Architecture Software Developer's Manual, Volume 2: Instruction Set Reference Manual
• Intel Architecture Software Developer's Manual, Volume 3: System Programming Guide
  
• Note: these manuals use a different syntax than the gnu "as" assembler (they have the order of operands reversed) 

GNU Assembler

• Manual for the as assembler
  

Assembling and linking commands

Under the cygwin environment, the assembling and linking commands for an assembly file "file.s" are:

as -o file.o file.s
ld -o file.exe file.o /lib/crt0.o libic.a -lcygwin -lkernel32

The library file libic.a is a collection of .o files bundled together, containing the code for the standard modules io and conv that are defined in the language specification, along with run-time support for garbage collection.