ch06

Isle Chapter 6 Software

This RISC-V software accompanies Input Output, chapter 6 of Building Isle. See also: Chapter 6 Hardware. Chapter 6 software uses instructions from the RV32IM ISA.

There's a blog post covering Chapter 6 Software.

Chapter 6 Programs

• echo.s - echos back a line of UTF-8 text (supports backspace)
• framecount.s - decimal frame counter
• guess.s - number guessing game
• num_str.s - tests number string conversion
• resolution.s - print display and text mode resolutions

Building Isle Software

If you've previously built chapter 5 software, you have everything you need. Consult the Isle Software Build guide for advice on setting up the toolchain.

Before building, ensure BIN_PREFIX in isle/software/book/ch06/Makefile matches your toolchain.

To build all the chapter 6 software:

cd isle/software/book/ch06
make

The software is assembled and turned into a .mem file suitable for loading into memory at design time.

To create a disassembled version of the linked software, run make with the program name and the .dis extension; for example:

cd isle/software/book/ch06
make echo.dis

To change the software run for chapter 6, amend FILE_SOFT in your dev board's top_ch06.v file. For example, to run echo:

localparam FILE_SOFT = {SW, "/book/ch06/echo.mem"};

Memory Map

Chapter 6 uses a simplified memory map with a 16-bit address that can address 64 KiB:

• 0x0000 - clut (to 0x00FF - 256 bytes)
• 0x4000 - tram (to 0x5FFF - 8K)
• 0x8000 - sysram (to 0xBFFF - 16K)
• 0xC000 - system device (to 0xCFFF - 4K)
• 0xD000 - graphics device (to 0xDFFF - 4K)
• 0xE000 - uart device (to 0xEFFF - 4K)

The stack pointer (sp) points to the address above the top of memory, 0xC000, and we decrement it to allocate space on the stack.

You can find hardware registers in the device modules in hardware/book/ch06.