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FantASM 1.7.5 is available

July 20, 2026FantASM

FantASM 1.7.5 is available to download.

What’s new

Added

  • Data-driven memory model per target: the Next pages in 8 KiB pages/slots, the 128K in 16 KiB banks. New page N, slot S directive maps any 8 KiB page into a slot (including odd pages 16 KiB banking can’t express); bank N, slot S now targets any window, not just $C000.
  • Paging-aware !test simulator: runs paged code with a live MMU — NEXTREG, the NEXTREG I/O ports ($243B/$253B) and the 128K paging port ($7FFD) remap slots during execution.
  • Device-variant selection: --ram (or fantasm.toml [assembler] ram) 2mb/1mb/512k range-checks bank/page numbers against the real RAM.
  • Paging builtins _page, _bank and _slot — the current instruction’s physical 8 KiB page, its 16 KiB bank, and slot index.
  • NEX generation checks: warn when the output has no code, or the entry point lands in an empty bank.
  • Online update check: --check-updates reports whether a newer FantASM is available; a throttled notice also shows on the startup banner (disable with FANTASM_NO_UPDATE_CHECK or the update-check build feature).

Fixed

  • An empty parenthesised operand (e.g. ld a,()) is now a syntax error instead of silently assembling as (0).
  • SLD output now conforms to the sjasmplus SLD v1 format: L label records replace the deprecated F, the Z device record carries the source file, spurious T records are gone, the non-standard E record is removed, and <page> numbers are banking-correct.

Changed

  • Test coverage expanded from 304 to 341 tests.

Get it from the Downloads page.