nx_nishios_irq.nx

nx_nishios_irq.nx -- NishiOS GUI rung-8: LIVE PS/2 IRQ1 (real interrupt-driven keyboard). Closes the "input is scripted" seam. The emu now models hardware INTERRUPT DELIVERY: between instructions, if IF (interrupt flag) is set and the keyboard controller has a pending scancode, the CPU TAKES the interrupt -- pushes the return address, vectors through the IDT entry idt[0x21] to the handler, which reads the scancode via INB port 0x60, stores it, and IRETs. The handler runs ONLY because an interrupt was delivered, not because anyone called it. Kernel: install idt[0x21], STI, then wait until N keys handled. We inject the scancodes for "nishi" as IRQs. KAT: all 5 keys arrive via the interrupt path (handler fired 5x, scancodes match); a NEGATIVE CONTROL with interrupts masked (no STI) collects ZERO -> proves delivery is genuinely IF-gated (real interrupt, not a disguised direct call); the scancodes translate to "nishi"; rendered to a terminal BMP. HONEST SEAM: scancodes are injected by the harness (a real PS/2 controller chip on hardware is R10); the IDT vectoring + IF-gating + INB + IRET are real. No hw writes (Rule 26). expect_exit: 0 tier: ORIGINAL