Transparancy Writes

[Yazwh0]

There are two mentions of this flag. One in the Affine helper section:

The Transparent Writes toggle in FX_CTRL is especially useful in Affine helper mode. Setting this toggle causes a write of zero to leave the byte (or the nibble) at the target address intact. This toggle is not limited to affine helper mode, and it affects writes to both DATA0 and DATA1.

and one in its own, which is under the Cache.

Transparent writes, when enabled, also applies to cache writes. If enabled, zero bytes (or zero nibbles in 4-bit mode) in the cache, which are treated as transparency pixels, are not written.

As this flag's effect reaches over all the modes of operation, should it have its own section explaining how it works? For example, what happens for 'normal' writes, or in combination with the 'One-byte cache cycling' functionality? How does it all work with '4 bit mode' for normal operation?

[Yazwh0]

Worth adding that transparency write disables the mask from the data being written being applied.