vgsp-gl: close a BEGIN/END pair carried into the draw window

r1526's first calls-kept draw window faulted with a GR class error at
SET_FRONT_FACE (0x191c <- 0x901) EC 0x0d ILLEGAL_METHOD_IN_BEGIN_END:
the window entered with a BEGIN..END pair still open from the previous
emitted window, so the first client state method ran inside it. With the
prelude CALL runs kept (iram_gate=0, hold_settle=0), r1529 then executed
the draw macro (mac=0x22) with zero class errors and engine-side page
writes.

Add sema_gl_pair_close_entry (default 0, A/B): when the pair tracker
carries an open pair into the window, emit the driver's own END form
(0x1614 + event word, event 1 for split chains 1/2) before the first
window run, then let the normal walk rebase the model. Receipt:
PAIR-CLOSE-ENTRY split/ev/window. r1532 showed the close can misfire
after refused launches (the injected END itself faulted at 0x1614), so
the parameter stays off by default until the model is committed only on
retire.

0 files changed, 0 insertions, 0 deletions