Docsity
Docsity
Prepare for your exams
Prepare for your exams

Study with the several resources on Docsity

Earn points to download
Earn points to download

Earn points by helping other students or get them with a premium plan

Guidelines and tips
Guidelines and tips
Sell on Docsity
Sell on Docsity
Docsity AI
Docsity AI
Log inSign up

Prepare for your exams

Study with the several resources on Docsity

Find documents

Prepare for your exams with the study notes shared by other students like you on Docsity

Search for your university

Find the specific documents for your university's exams

Docsity AINEW

Summarize your documents, ask them questions, convert them into quizzes and concept maps

Explore questions

Clear up your doubts by reading the answers to questions asked by your fellow students

Earn points to download

Earn points by helping other students or get them with a premium plan

Share documents
download point icon20 Points

For each uploaded document

Answer questions
download point icon5 Points

For each given answer (max 1 per day)

All the ways to get free points
Get points immediately

Choose a premium plan with all the points you need

Study Opportunities

Choose your next study program

Get in touch with the best universities in the world. Search through thousands of universities and official partners

Community

Ask the community

Ask the community for help and clear up your study doubts

Free resources

Our save-the-student-ebooks!

Download our free guides on studying techniques, anxiety management strategies, and thesis advice from Docsity tutors

Procedures and Calling Conventions in PowerPC Assembly, Study notes of Electrical and Electronics Engineering

University of Michigan (UM) - Ann ArborElectrical and Electronics Engineering

The concept of procedures in assembly and high-level languages, focusing on powerpc architecture. It covers application binary interfaces, calling conventions, recursive calls, and examples. The document also discusses the powerpc isa features for procedure calls and the use of the stack.

Typology: Study notes

Pre 2010

Uploaded on 09/02/2009

koofers-user-fo9-1
koofers-user-fo9-1 🇺🇸

10 documents

1 / 4

Toggle sidebar

This page cannot be seen from the preview

Don't miss anything!

bg1
Procedures
Procedures are very important for writing
reusable and maintainable code in assembly
and high-level languages. How are they
implemented?
• Application Binary Interfaces
• Calling Conventions
• Recursive Calls
• Examples
Reference: PowerPC Embedded ABI
General Concepts
• Caller: The calling procedure
Callee: The procedure called by the caller
… int mult(x, y)
prod = mult (a, b) …
… return (x * y)
• Caller and callee must agree on:
• How to pass parameters
• How to return the return value(s), if any
• How to maintain relevant information across calls
• PowerPC architecture does not define “agreement”. Instead,
common policies are defined by convention.
PowerPC Features
The PowerPC ISA provides the following features to support
procedure/function calls:
• link register (p. 2-11)
• bl: branch and link (p. 4-41)
• blr: branch to link register (Table F-4)
A Very Simple Calling Convention
• Passing arguments
• Use GPRs r3 to r10 in order
• Use stack in main memory if more than 8 arguments
• Passing return value
• Leave result in r3
pf3
pf4

Partial preview of the text

Download Procedures and Calling Conventions in PowerPC Assembly and more Study notes Electrical and Electronics Engineering in PDF only on Docsity!

Procedures

Procedures are very important for writingreusable and maintainable code in assemblyand high-level languages. How are theyimplemented?• Application Binary Interfaces• Calling Conventions• Recursive Calls• ExamplesReference: PowerPC Embedded ABI

General Concepts

  • Caller: The calling procedureCallee: The procedure called by the caller…

int mult(x, y)

prod = mult (a, b)

return (x * y)

  • Caller and callee must agree on:
    • How to pass parameters• How to return the return value(s), if any• How to maintain relevant information across calls
      • PowerPC architecture does not define “agreement”. Instead,common policies are defined by convention.

PowerPC Features

The PowerPC ISA provides the following features to supportprocedure/function calls:• link register (p. 2-11)• bl: branch and link (p. 4-41)• blr: branch to link register (Table F-4)

A Very Simple Calling Convention

  • Passing arguments
    • Use GPRs r3 to r10 in order• Use stack in main memory if more than 8 arguments
      • Passing return value
        • Leave result in r

Example

int func(int a, int b){

return (a + b); } main{

…func(5,6);… }

Another Example

int func2(int a, int b){

return func(a , b); } main{

…func2(5,6);… }

The Stack

  • Information for each function invocation (e.g. link register) is savedon the

call stack

or simply

stack

  • Each function invocation has its own

stack frame

(a.k.a.

activation

record

func2func

stack framestack frame

stackpointer high address low address

Using the Stack

main

……bl

func …

func

……bl

func …??…

func

Describe the stack and LR contents• right before the first bl• right after the first bl• right after the second bl• after each procedure returns

EABI Stack Frame^ FPRs (optional, var size)GPRs (optional, var size)

CR (optional, 1 word)

local variables (optional, var size) function param’s (optional, var size) Padding (make size mult of 8 bytes)

Link Register^ Back Chain

frameheader

highestaddress lowestaddress