Notes

• All sh_vmu_* screen functions are zero-cost wrappers around KOS vmufb.
• Save functions wrap the vmu_pkg + vmufs dance into one call.
• sh_vmu_addr_t gives name-based addressing (“port A, slot 1”) without string parsing overhead.
• No desktop virtual screen in Shachi — that’s a dev tool concern, not SDK.

Spec 2: SH4 Math (shachi/sh4math.h)

Problem

KOS has dc/fmath.h (basic FSRRA/FSCA wrappers) and dc/matrix.h (XMTRX operations). Moopthehedgehog’s DreamHAL sh4_math.h (public domain, 2020) provides comprehensive FTRV/FIPR/FSCA intrinsics with proper pipeline hazard management. We need to decide: wrap, adopt, or compose.