Generated programs kept their state in system zero page $C0-$FE, which on the
C128 is KERNAL and screen-editor state while CHROUT runs: the print runtime's
pointer and length sat on TCOLOR/RVS/QTSW ($F2-$F4), and the KERNAL IRQ clears
its index at $C0 (CAS1). HELLO.PRG printed "HELLO FROM NOVA1ELLO FROM NOVA128"
in reverse video, which 8f8cf00 had hidden by masking bit 7 in the check.

The ENTRY stub now masks IRQs, installs CR $0E (D129), points P0 at page $1A,
sets the frame base, calls CODE and START, then restores P0, CR and flags.
prgprint switches P0 back to $0000 only around each CHROUT, inlined to stay
position independent. The driver test no longer masks reverse video.

The larger runtime exposed an 8-bit overflow in the driver's CODE base
(ENTRY + START + PRINT now exceeds 255 bytes, which surfaced as DISK ERROR);
the driver now passes the 16-bit address it already computes.

Full regression: 25 of 26 suites pass; parser fails only on baseline hashes
that predate 221e0c5.