aLec16_localVariables

# aLec16_localVariables - Introduction to Embedded...

This preview shows pages 1–2. Sign up to view the full content.

Lecture 16.1 Jonathan W. Valvano Student: “Programming in assembly is a lot like digging a post hole with a teaspoon. Of course, you do have complete control over every piece of dirt” Valvano: “Programming in a high level language is a lot like painting a masterpiece with a paint roller. Of course, you do get the job done quickly.” Recap Finite State Machines Pointer implementation Overview Fixed-point: why, when, how Local variables: scope and allocation How these concepts apply to C Binding, allocation, access, deallocation 10.1. Fixed-point numbers Fixed point numbers Why? (wish to represent non-integer values) Next lab measures distance from 0 to 3 cm E.g., 1.234 cm When? (range is known, range is small) Range is 0 to 3cm Resolution is 0.003 cm How? (value = Integer* Δ ) 16-bit unsigned integer Δ = 10 -3 decimal fixed-point Range becomes 0.000 to 65.535 Output an integer. Assume integer, n, is between 0 and 9999. not very pretty OutChar(\$30+n/1000) ;thousand’s digit n = n%1000 OutChar(\$30+n/100) ;hundred’s digit n = n%100 OutChar(\$30+n/10) ;ten’s digit OutChar (\$30+n%10) ;one’s digit Output a fixed-point number. Assume the integer part of the fixed point number, n, is between 0 and 9999. very pretty OutChar(\$30+n/1000) ;thousand’s digit n = n%1000 OutChar(\$2E) ;decimal point OutChar(\$30+n/100) ;hundred’s digit n = n%100 OutChar(\$30+n/10) ;ten’s digit OutChar (\$30+n%10) ;one’s digit 7.3. Local Variables Introduction

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

## aLec16_localVariables - Introduction to Embedded...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online