Force SYS68K/CPU-30 R4, Техническое справочное руководство

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FGA Boot Software SYS68K/CPU-30 R4 Technical Reference Manual
Page 180
10.1 AS - Line Assembler
Format: AS <address>
The AS command invokes the line assembler of the FGA-002 Boot
Software. It can assemble and disassemble all 68020/30/40 mnemonics
and 68881/82 floating point instructions.
The AS command, when invoked, displays the current address and
disassembles the opcode at this location.
After the prompt on the next line, the user can enter one of the following:
1. A valid 680x0 mnemonic. Some addressing modes allow omission of
arguments. These addressing modes can be entered by omitting the
argument and typing the dividing character ",".
Examples:
CLR.W ([$1,A0],D0.W,$2)
CLR.W ([$1,A0],,$2)
CLR.W ([,A0],,)
2. A ’#’ sign followed by the new address changes the address counter
to this absolute address.
3. An ’=’ disassembles the same location again.
4. A ’+’ or <Return> disassembles the next location.
5. A ’+’ or ’-’ sign followed by the number of bytes increases/decreases
the address counter.
6. A ’.’ or <ESC> allow to exit the line assembler and return control to
the command interpreter.
7. <Ctrl-A> copies the current disassembled opcode in the line buffer.
This allows editing the current mnemonic.
All immediate values, addresses, and offsets used within mnemonics are
assumed to be entered in decimal. Hex values have to be specified with a
dollar sign ’$’. In addition, binary values can be entered by a preceding
percent sign ’%’, octal values by an at sign ’@’. The disassembler
displays all values in hex representation.
The line assembler accepts also pseudo opcodes of the form
DC.B
,
DC.W
and
DC.L
to define constant data storage. An ASCII pattern can be
stored by using
DC.B
with the format ’
DC.B "text
’. All characters
after the ’"’ will be interpreted as ASCII characters and stored into
memory.