One of the early Microsoft 6502 Basic versions, made for the SYM-1.
Two versions were made. The first came as two 4K ROMS, V1.1 as one 8K ROM. ROM ID BAS 023-0025A.
The tri-goniometric functions, an option at startup are documented in the Basic manual as hex dump or on page 27 in the Technotes
There were two versions of the BASIC ROMs available.

• A two ROM set (part numbers 02-0019-01 and 02-0020-1). These went into sockets U21 and U22 respectively.
• A single ROM (part number 02-0058 A/B). This went into socket U21. It’s 8K and it’s position dependent. It fits in from $C000 to $DFFF.

The 8k Basic has tokens but no code for the trig functions. There’s an application note which invites you to type in the hex and save to tape the approx 512 extra bytes needed. See page 27 of the tech notes.

The 1981 manual shows the correct jumpers for an 8K ROM in U21. The 1978 manual shows the correct jumpers for two 4K ROMs in U21 and U22

BASIC Manual second printing.

ROM binaries

• Basic v.1.0 first ROM at C000
• Basic v.1.0 second ROM at D000
• Basic V1.1 8K ROM at C000
• TRIG object code dump form Basic and TEchnotes
• Ascii dumps of V1.1 and information by Leland Goertz
• Loadable extended SYM-1 BASIC by John JOHN W. Brown 1980 SATURN SOFTWARE: TRACE, TIME etc ($0200-11FF)
• Loadable SYM-1 Basic extensions (tape?) ($1200-1705)
• Disassembly by Lee Davison of V1.1

BXT_1200 is just 1285 useful bytes, and then filled with FF. It contains the strings PERFECT MATCH!, COMPARE ERROR AT, CHECK SUM ERROR! and INVALID DELETE RANGE!

BXT_0200 is a full 4k bytes, and contains these strings:
FOUND LOADING SEARCHING FOR SAVING CALL STIME EDIT PAGE TRACE CHAIN EXEC PAGE EXTENDED SYM-BASIC BY JOHN W. BROWN COPYRIGHT (C) 1980 SATURN SOFTWARE LIMITED