The Atmel AT750 is roughly two 22V10 chips in a DIP20 package,  It probably seemed a good idea at the time, but it never took off to become a standard component,  so the official data sheet says 'not recommended for new designs' even though it can be ordered.

SHIFT.PLD effectively replaces an LS374 eight-bit data latch and an LS165 shift register, IC5 and IC9 of the original ZX80.

HSYNC.PLD works like an LS393 counter and an LS688 comparator to reset the counter after 208 (states 0 to 207). Extra logic generates the sync pulses. The logic is complicated by coping with four machines, the ZX80, ZX81, and two Lambda variants. Each pin can have different clock sources, unlike the 22V10 which has one clock for all output pins. Teasing this logic into two or more different chips will require some careful thought.