dot commands and interrupts

Hi,

When a dot command is running, divIDE/MMC is paged in so an interrupt will just return as you say. esxDOS syscalls do use IY but it is pushed and popped when exiting.

IM2 loading works from BASIC and from machine code (not from .TAP files for now), but the IM2 routine must be set to normal Speccy RAM.

First successful dot command compiled from C and emulated in ZEsarUx:
https://drive.google.com/file/d/0B6XhJJ … sp=sharing

.bmp2next zxnext.bmp zx-new.bmp

converts a 256-colour bmp image of arbitrary size to a 256-colour bmp using the Spectrum Next's RRRGGGBB palette.

I clearly have some of the mode bits for file open wrong.

Here is what I am using now:

# File Access Mode

define(`__ESXDOS_MODE_READ', 0x01)            # read access
define(`__ESXDOS_MODE_WRITE', 0x02)           # write access
define(`__ESXDOS_MODE_OPEN_EXIST', 0x00)      # open if exists else error
define(`__ESXDOS_MODE_OPEN_CREAT', 0x08)      # open if exists else create
define(`__ESXDOS_MODE_CREAT_NOEXIST', 0x04)   # create if no exist
define(`__ESXDOS_MODE_CREAT_TRUNC', 0x0c)     # create and/or truncate
define(`__ESXDOS_MODE_USE_HEADER', 0x40)      # use +3DOS header passed in DE

I'm hoping you can correct / add info about the file open mode flags.

Thanks!

There's some confusion about what the bits are doing.  Some emulator authors are using at least one of the modes to open files for append writes, which I seem to recall esxdos doesn't do.  (I don't have real hardware so I have to test under emulation).

For example, I opened a file with flags "ESXDOS_MODE_W | ESXDOS_MODE_OC" (0x0a) and the emulation caused all writes to append to an existing file.

Maybe this can be sorted out if a description of the mode bits can be spelled out:

# File Access Mode

There is one file pointer shared by read and write

define(`__ESXDOS_MODE_READ', 0x01)            # read access
define(`__ESXDOS_MODE_WRITE', 0x02)           # write access

define(`__ESXDOS_MODE_OPEN_EXIST', 0x00)
Open if the file exists else return an error.
The file pointer points at the beginning of the file.
Writes will overwrite file contents as the fp moves forward.

define(`__ESXDOS_MODE_OPEN_CREAT', 0x08)
Open if the file exists else create a new file.
The file pointer points at the beginning of the file.
Writes will overwrite file contents as the fp moves forward.

define(`__ESXDOS_MODE_CREAT_NOEXIST', 0x04)
If the file exists return error else create a new file.

define(`__ESXDOS_MODE_CREAT_TRUNC', 0x0c)
Create a new file or empty an existing one.

define(`__ESXDOS_MODE_USE_HEADER', 0x40)      # use +3DOS header passed in DE

Also I want to confirm that files opened with both RW mode enabled is allowed.  They share the same file pointer so that you can alternate reads/writes and seek through the file.  The emulators are not allowing this.

In the bmp2next.c dot command in the zip I linked, I'm doing this for the case where bmp2next is not given an output filename as in ".bmp2next zxnext.bmp".  In this case the file "zxnext.bmp" is opened in RW mode so that it can be modified in place.  The program reads X bytes into a buffer, operates on it, seeks backward by X bytes and then writes X bytes.  This repeats until the entire file has been processed.

Cheers lordcoxis.  I'm pretty sure I have things right now.  Hopefully the emulators will catch up soon.

Hi,

Drive '$' just points to the drive here the system files reside. So you need to open /BIN/FOO.DTX. I don't actually remember but I think if you type .foo.dtx it will try to load it yes (I'm working on v0.9.x right now, where it's different). The music tracker players by gasman (playstc, playpt3 and playsqt) do try to allocate memory from main RAM to load the musics (if needed), and return Out of Memory error if they fail.