acornaeologyThe Shape of Things That Run

Acorn NFS 3.62 Memory Map

← Acorn NFS and Acorn ANFS

Addresses outside the ROM used by Acorn NFS 3.62 at run time — zero-page workspace, RAM buffers, and memory-mapped I/O. For the ROM code itself (&8000–&9FFF), see the disassembly listing.

Access: R read, W write, B indexing base — the address is named as base,X/,Y, so the byte actually touched is base + index and the literal byte at this address is never itself accessed.

Zero page

Address Name Access Description
&0002 zp_work_2 B
&0003 zp_work_3 B
&00AE work_ae B
&00AF addr_work B
&00C2 txcb_dest B
&00C7 txcb_pos B

6502 stack page

Address Name Access Description
&0101 error_text B
&0102 stk_timeout_mid B
&0103 stk_frame_3 B
&0104 stk_timeout_hi B
&0106 stk_frame_p B
&0128 tube_osword_pb B

RAM workspace

Address Name Access Description
&0700 string_buf B
&0CFF nmi_code_base B
&0D1A nmi_shim_1a B
&0D1E tx_addr_base B
&0D26 tx_data_start B
&0D41 rx_remote_addr B
&0D58 exec_addr_lo B
&0DE6 nmi_sub_table B
&0DEB fs_state_deb B
&0DF0 rom_ws_table B
&0DFE fs_context_base B
&0E30 fs_filename_buf B
&0EF7 fs_reply_data B
&0F0D fs_file_len B
&0FE0 fs_error_buf B

Indexing-base addresses (wrap into ZP)

Address Name Access Description
&7DFD tx_ptr_sub_base B