From e19e8f1a9124a87b859bd8e1cab5ad0a07892bdd Mon Sep 17 00:00:00 2001 From: oharboe Date: Thu, 21 Aug 2008 21:36:29 +0000 Subject: more docs merged into the big doc --- zpu/roadshow/roadshow/codesize/index.html | 58 ------------------------------- 1 file changed, 58 deletions(-) delete mode 100644 zpu/roadshow/roadshow/codesize/index.html (limited to 'zpu/roadshow/roadshow/codesize') diff --git a/zpu/roadshow/roadshow/codesize/index.html b/zpu/roadshow/roadshow/codesize/index.html deleted file mode 100644 index 3f61b4e..0000000 --- a/zpu/roadshow/roadshow/codesize/index.html +++ /dev/null @@ -1,58 +0,0 @@ - - -

Compiling hello world program with the ZPU GCC toolchain

-The ZPU comes with a standard GCC toolchain and an instruction set simulator. This allows compiling, running & debugging simple test programs. The Simulator has -some very basic peripherals defined: counter, timer interrupt and a debug output port. -

Installation

Install Cygwin. http://www.cygwin.com -
Start Cygwin bash -
unzip zputoolchain.zip -
Add install/bin from zputoolchain.zip to PATH.
-export PATH=$PATH:/install/bin -

Hello world example

-The ZPU toolchain comes with newlib & libstdc++ support which means that many C/C++ programs can be compiled without modification. -

--zpu-elf-gcc -Os -zeta hello.c -o hello.elf -Wl,--relax -Wl,--gc-sections -zpu-elf-size hello.elf - -

Optimizing for size

-The ZPU toolchain produces highly compact code. -

Since the ZPU GCC toolchain supports standard ANSI C, it is easy to stumble across -functionality that takes up a lot of space. E.g. the standard printf() function is a beast. Some compilers drop e.g. floating point support -from the printf() function and thus boast a "smaller" printf() when in fact they have a non-standard printf(). newlib has a standard printf() function -and an alternative iprintf() function that works only on integers. -
The ZPU ships with default startup code that works across various configurations of the ZPU, so be warned that there is some overhead that will -not occurr in the final application(anywhere between 1-4kBytes). -
Compilation and linker options matter. The ZPU benefits greatly from the "-Wl,--relax -Wl,--gc-sections" options which is not used by -all architectures(e.g. GCC ARM does not implement/need -Wl,--relax). -

Small code example


-zpu-elf-gcc -Os -abel smallstd.c -o smallstd.elf -Wl,--relax -Wl,--gc-sections

-zpu-elf-size small.elf

-

-$ zpu-elf-size small.elf

-   text    data     bss     dec     hex filename

-   2845     952      36    3833     ef9 small.elf

-

-

- -

Even smaller code example

-If the ZPU implements the optional instructions, the RAM overhead can be reduced significantly. -

--zpu-elf-gcc -Os -abel crt0_phi.S small.c -o small.elf -Wl,--relax -Wl,--gc-sections -nostdlib -zpu-elf-size small.elf - -$ zpu-elf-size small.elf - text data bss dec hex filename - 56 8 0 64 40 small.elf - - - - - -- cgit v1.1