Re: C code .vs. Assembly code for Microcontrollers/DSPs ?

schwarz@mips.complang.tuwien.ac.at (Konrad Schwarz)
25 Mar 1996 21:52:39 -0500

          From comp.compilers

Related articles
[42 earlier articles]
Re: C code .vs. Assembly code for Microcontrollers/DSPs ? jfc@mit.edu (1996-03-22)
Re: C code .vs. Assembly code for Microcontrollers/DSPs ? chuck@aage.mit.edu (1996-03-22)
Re: C code .vs. Assembly code for Microcontrollers/DSPs ? preston@tera.com (1996-03-22)
Re: C code .vs. Assembly code for Microcontrollers/DSPs ? bobduff@world.std.com (1996-03-22)
Re: C code .vs. Assembly code for Microcontrollers/DSPs ? torbenm@diku.dk (1996-03-25)
Re: C code .vs. Assembly code for Microcontrollers/DSPs ? kanze@lts.sel.alcatel.de (James Kanze US/ESC 60/3/141 #40763) (1996-03-25)
Re: C code .vs. Assembly code for Microcontrollers/DSPs ? schwarz@mips.complang.tuwien.ac.at (1996-03-25)
Re: C code .vs. Assembly code for Microcontrollers/DSPs ? pardo@cs.washington.edu (1996-03-25)
Re: C code .vs. Assembly code for Microcontrollers/DSPs ? mgrice@iastate.edu (1996-03-27)
Re: C code .vs. Assembly code for Microcontrollers/DSPs ? sberg@camtronics.com (1996-03-31)
Re: C code .vs. Assembly code for Microcontrollers/DSPs ? nather@astro.as.utexas.edu (R. Edward Nather) (1996-04-02)
Re: C code .vs. Assembly code for Microcontrollers/DSPs ? ok@cs.rmit.edu.au (1996-04-02)
Re: C code .vs. Assembly code for Microcontrollers/DSPs ? sberg@camtronics.com (1996-04-06)
[1 later articles]
| List of all articles for this month |

From: schwarz@mips.complang.tuwien.ac.at (Konrad Schwarz)
Newsgroups: comp.arch,comp.compilers,comp.dsp
Date: 25 Mar 1996 21:52:39 -0500
Organization: TU Wien
References: 96-03-006 96-03-091 96-03-111 96-03-142
Keywords: optimize, performance

Our moderator writes:
|> [If you have an auto variable and never take its address, it can't be
|> aliased. Register does document your intent, but it doesn't tell the
|> compiler anything it can't figure out anyway. -John]


This contradicts advice found in the ``Programmer's Guide'' for DEC Unix.
Chapter 7, ``Optimizing Techniques,'' section 7.12.2, says:


Use register declarations liberally. The compiler
automatically assigns variables to registers. However,
specifically declaring a register type enables the
compiler to make more aggressive assumptions when
assigning register variables.


Past experiments with a HP compiler verify this.


Konrad Schwarz
[Well, OK, but I'd sure like to know what the more aggressive assumptions
are. -John]


--


Post a followup to this message

Return to the comp.compilers page.
Search the comp.compilers archives again.