Andy

@aeiou.bsky.social

29 Followers 116 Following

Old computers, baking, and biking

Mini-assembler and disassembler All models of the Apple Il have some version of the disassembler, and all but the early models of the Apple Ile have a mini-assembler. The Apple IIGS has both. They are enhanced to support the 65C816 microprocessor's new instructions and long addresses, and they support both native and emulation mode. The mini-assembler and disassembler are special features of the Monitor. The mini-assembler provides a means of developing and debugging a program or routine in a very simple form of assembly language. When you invoke the mini-assembler, the prompt character changes to an exclamation point @ and the Monitor accepts 65C816 instructions in the form address: opcode operands The address field and the colon are optional; you omit them to enter consecutive instructions. The mini-assembler does not maintain a symbol table, but it does recognize all the standard instruction mnemonics, and it calculates relative addresses. It recognizes a preceding number sign (*) as signifying an immediate operand. You use the letters X and Y, set off by commas, for indexing, and you type indirect addresses inside parentheses. To stop the mini-assembler, you type a null line by pressing the Return key. Unlike the mini-assembler, which takes over the user interface and accepts inputs from the user, the disassembler is just the Monitor's List command. It lists the contents of memory, one screenful at a time, converting op codes into mnemonics and relative addresses into absolute addresses. Both the mini-assembler and the disassembler can handle all 91 of the 6SC816's instructions and all 24 addressing modes (a total of 256 op codes). In addition, the disassembler properly expands operating-system calls to ProDOS 8 and ProDOS 16, showing command numbers and parameter-list pointers on separate lines.
Macintosh IIci running Netscape Navigator 2.02 loading up an article about the SNES.
Photo of a Macintosh IIci running Netscape Navigator. There is an Network Error dialog box on the screen.
The inside of a SEPTA commuter rail car. The inside has been decorated with string lights, snowflake decals, merry christmas signs, and garlands. It's quite excessive, but very charming!
A photo of 14th St Union Square station. It's from above the local downtown track, a 6 train is coming in around the curved platform. People are waiting on the platform. There is a fenced in walkway above where people are walking too.