Developing a native pascal/c compiler for 65c816 one problem is implement new()/dispose() procedures and malloc()/free() functions that take advantage of large memory addressable by cpu.
In attached file an attempt of a possible implementation of 2 routines:
- GetMem: allocate a block of memory from ...

...but I didn't fully understand why you didn't think of an FPGA implementation of your "C16" project as you can write Verilog code and this technology would have provided you the design flexibility and cost reduction...

Good question. My goal was built a machine with a serious O.S. using old ...

Hi Webst, as told, when i developed this code i planned to built a real 65c02 system. I uploaded this code for 2 raisons: 1) share with other peoples (in forum many threads about MMU for 6502). 2) Have feedback not just about verilog implementation, but especially about my approach to a possible MMU ...

Hi webmast,

in last years my interest is migrated to 65816 projects (even if i builts two 65c02 projects: one is on my web site, the one other is based on a banked-scheme similar to the one used on the plus/4), so i lose interest on stricty 6502 uP.
If you want implement a fully 8722 in HDL the ...

Still one note regarding the DBE signal...

You have implemented this input in order to (externally) manage contention on the cpu data bus when registers are read, still in a real 8722MMU there is not such a port and there isn't any external "chip select" detection logic for the MMU in a C128. So ...

A simple ISR for uart 16c550 + 65c816 is here:

http://65xx.unet.bz/c16sw/

Uart work in fifo mode, can handle these baud rates: 38,400 - 57,600 - 115,200 - 230,400 (uart clocked at 3.6864Mhz), and allow both hardware handshake (through standard null-modem or uplink cable) and software handshake ...

Just as contribution to this discussion, in my c16 computer i'm developing system calls through 'cop' instruction; i use 'signature byte' as 'function number'.
For example, printing a character to console, is accomplished with this code:


lda #'A'
cop $00


The code i use for cop handler can be ...

I agree with GARTH, but with an additional comment.

In some applications losing accurance in computation can give very bad pratical result; in GPS the cancellation error due to the computing differences of numbers about fractions of uS, can give a wrong position about hundreds meters (for no say ...

Hello,

i'm developing a "c-like" printf() family function, in assembler, for the 65c816 uP.
Six function are in develop here:

1) cprintf(lpFmt, ..., wCount) - format parameters basis the format string and print on console
2) tprintf(lpFmt, ..., wCount) - print on default text device (useful for ...

The rounding error while basic operations is indipendent from the base. The only justification for use decimal base is the rounding error due to the conversion from binary to decimal string. This conversion involve a scaling by powers of ten until the number fall into a wanted range, then is treated ...

in an 8 bit micro this is important?

Just for say: no matter the base used, any machine work with a finite number of bits, or nibbles, or digits, so in any base the range of number is just one restricted subset of irrational number, and with variable distance between consecutive numbers.

Just as suggestion: why don't use the Microsoft 5 bytes f.p. implementation as in commodore line?

@Chromatix

Actually, for basic operations in my implementation i use a full 128 bits mantissa (15 guard bits), with usual rounding to the nearest. In division algorithm i use 2 more bits for last remainder (at some point the infinite cycle must be stopped), and i use the msb for round the 128 bits ...

65C02 based desk calculator, now that's a nice idea.
The problem when implementing a floating point package is, that the devil hides in the detail.
For instance, in the rounding errors when calculating polynomials for having transcendental functions.


Are used rational function's, in a strict ...