mirror of
https://github.com/uffejakobsen/acme.git
synced 2024-11-22 18:32:09 +00:00
465da8c139
fixed a bug where "number out of range" error led to bogus "label already defined" errors made "number out of range" errors more specific (8/16/24 bit range) re-phrased two error messages cleaned up docs concerning "command/opcode/mnemonic/instruction" added test program to trigger "out of range" errors internal cleanup concerning INW/DEW/JAM mnemonics git-svn-id: https://svn.code.sf.net/p/acme-crossass/code-0/trunk@278 4df02467-bbd4-4a76-a152-e7ce94205b78
89 lines
3.3 KiB
Plaintext
89 lines
3.3 KiB
Plaintext
|
|
|
|
ACME
|
|
|
|
...the ACME Crossassembler for Multiple Environments
|
|
|
|
--- 65816 support ---
|
|
|
|
|
|
This text contains information about the 65816-specific features of
|
|
ACME.
|
|
|
|
|
|
----------------------------------------------------------------------
|
|
Section: Aliases for "long" JMPs and JSRs
|
|
----------------------------------------------------------------------
|
|
|
|
In addition to the mnemonics JMP and JSR, the 65816 processor also
|
|
knows JML and JSL, which are JMP and JSR using new (long) addressing
|
|
modes. ACME also accepts the new addressing modes when using the old
|
|
mnemonics JMP and JSR, but the old addressing modes cannot be used
|
|
with the new mnemonics JML and JSL.
|
|
|
|
|
|
----------------------------------------------------------------------
|
|
Section: Argument order of MVN/MVP
|
|
----------------------------------------------------------------------
|
|
|
|
According to WDC's official syntax for 65816 assembly language, the
|
|
argument order of the MVN and MVP instructions differs between
|
|
assembly language and machine code.
|
|
To copy bytes from bank $ab to bank $cd, use the following statement:
|
|
mvn $ab, $cd ; source bank $ab, destination bank $cd
|
|
or
|
|
mvn #$ab, #$cd ; source bank $ab, destination bank $cd
|
|
ACME will then produce the following machine code:
|
|
$54 $cd $ab ; opcode mvn, destination bank $cd, source bank $ab
|
|
|
|
ACME 0.05 and earlier did it the wrong way.
|
|
|
|
|
|
----------------------------------------------------------------------
|
|
Section: Register lengths
|
|
----------------------------------------------------------------------
|
|
|
|
When assembling "lda #5" for example, ACME has to know whether to
|
|
create an 8-bit argument or a 16-bit argument. This depends on the
|
|
current register length.
|
|
On startup, ACME assumes all registers are 8 bits wide. You can change
|
|
this at any time using the following pseudo opcodes:
|
|
|
|
!al ; switch to long accumulator
|
|
!as ; switch to short accumulator
|
|
!rl ; switch to long index registers
|
|
!rs ; switch to short index registers
|
|
|
|
Please note that ACME, unlike some other assemblers, does *not* track
|
|
SEP/REP instructions: I don't like that method - it fails when
|
|
encountering PLPs, for example. So if it doesn't work reliably in the
|
|
first place, why use it? :)
|
|
|
|
If you don't like that you always have to use a pseudo opcode
|
|
alongside SEP/REP instructions, then have a look at the library file
|
|
<65816/std.a> which has some predefined macros you can use.
|
|
|
|
|
|
----------------------------------------------------------------------
|
|
Section: Postfixing stuff
|
|
----------------------------------------------------------------------
|
|
|
|
You can also use the postfix method (which is explained in the file
|
|
"AddrModes.txt") to specify the immediate argument's length:
|
|
|
|
ldx+2 #5
|
|
|
|
will always be assembled to a 16-bit argument, regardless of the
|
|
currently configured index register width. Use at your own risk - this
|
|
method obviously is not a good example on structured programming. :)
|
|
|
|
|
|
----------------------------------------------------------------------
|
|
Section: Miscellaneous
|
|
----------------------------------------------------------------------
|
|
|
|
Note that ACME cannot produce more than 64 KBytes of code. Also note
|
|
that though the 65816 CPU has an address space of 16 MB, ACME's
|
|
program counter is only sixteen bits wide. It shouldn't be too hard to
|
|
make any assembled code run in a non-zero bank, though.
|