SiDi128 Screen Rotation broken

[danyppc]

Screen rotation broken with yesterday 18 Jul 2026 on SiDi128

[jotego]

Glad to see that someone is using the SiDi128! I'll check it

[danyppc]

I own 3x SiDi128 (1 is of my brother), 2x MiSTica, 3x MiST
:)

[rp-jt]

@jotego Could this be related to commit 3bf8a4b ?
In this, modules/jtframe/target/mist/hdl/jtframe_mist_top.sv changes an endif for an else in line 144. So now we have this:

`ifdef MIST_DUAL_SDRAM

`ifdef JTFRAME_LF_SDRAM_BUFFER
`define MIST_USE_SDRAM2
`else
`ifdef JTFRAME_VERTICAL
`ifdef JTFRAME_SDRAM_ROTATION
`define MIST_USE_SDRAM2
`define MIST_USE_SDRAM2_ROTATION
`endif
`endif
`endif

In the former version, MIST_USE_SDRAM2_ROTATION is defined if JTFRAME_VERTICAL and JTFRAME_SDRAM_ROTATION are defined, independently from JTFRAME_LF_SDRAM_BUFFER, but now, both Rotation and frame buffer are incompatible.

Currently, MIST_USE_SDRAM2_ROTATION cannot be defined in SiDi128, because both MIST_DUAL_SDRAM=1 and JTFRAME_LF_SDRAM_BUFFER=1 are found in modules/jtframe/target/sidi128/target.def

[rp-jt]

Frame buffer should take priority over vertical video for gals to work, so I've tried using this block instead:

`ifdef MIST_DUAL_SDRAM

`ifdef JTFRAME_LF_BUFFER
`ifdef JTFRAME_LF_SDRAM_BUFFER
`define MIST_USE_SDRAM2
`endif
`else
`ifdef JTFRAME_VERTICAL
`ifdef JTFRAME_SDRAM_ROTATION
`define MIST_USE_SDRAM2
`define MIST_USE_SDRAM2_ROTATION
`endif
`endif
`endif

However, the resulting compilation showed no change when selecting Screen Rotation: YES in the sidi128 OSD menu. I was testing 1942 and Rumba Lumber
I've gone back to try older compilations and tested d8a8bd1, 0e5061e, and 864f26d and I had the same result with these games. The last one is from November 2025, so I'm not sure for how long this has been an issue

[jotego]

@gyurco could you have a look at this one? This feature came from you and we didn't really ever test it.
The gals core needs to use the secondary SDRAM for the object frame buffer, so it cannot do the rotation. But the rest of the cores should have kept working ok.
Now we cannot assert that this feature was even working before.

[danyppc]

Excuse me, with the core release of 05 July '26 screen rotation is ok.

[gyurco]

Checked a game (Fast Lane) and the problem seems that JTFRAME_LF_SDRAM_BUFFER is defined together with JTFRAME_SDRAM_ROTATION, and the former wins (as it should, as if a game requires the second sdram, it should get it). But most games doesn't need the framebuffer, so it shouldn't be defined. I'll check the root cause.

[gyurco]

In commit 488c659, JTFRAME_LF_SDRAM_BUFFER is defined unconditionally for SiDi128. Previously using the framebuffer was defined for specific games (maybe only Outrun).

[gyurco]

I fixed this once (before rotation was added, so the impact wasn't big):
2f7c5f5
It was simply reverted by
488c659

Not sure about the acceptable fix then.
My approach was to add to specific games, not globally to cores/game/cfg/macros.def
ecec7c6

[gyurco]

And while it was re-added globally in 488c659, it's still there for Outrun:

jtcores/cores/outrun/cfg/macros.def

Line 73 in 0620954

[sidi128]

I suggest this approach, add to games which are using it only.

[gyurco]

...and maybe add a notice to macros.md, like JTFRAME_LF_SDRAM_BUFFER - use it wisely, as it disables rotation! Add to games only which requires it.