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Added documentation and automatic execution of assembled source

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Andrew Alderwick 2021-05-15 21:49:46 +01:00
parent e289b359d8
commit 0d20b4309a
1 changed files with 57 additions and 9 deletions
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66
projects/software/asma.usm
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@ -5,9 +5,54 @@
( vectors )
(
Asma - an in-Uxn assembler
This assembler aims to be binary compatible with the output from
src/assembler.c, but unlike that assembler this one can be run inside Uxn
itself!
Asma is designed to be able to be copy-pasted inside another project, so
all its routines are prefixed with "asma-" to prevent clashes with labels
used in the incorporating project. The reset vector contains a couple of
examples of asma's usage and can be discarded.
)
|0100 @reset
(
Assemble the source code into an output ROM file.
If all you want is to use asma.usm to assemble files, insert a BRK
after this statement.
)
;&source-file ;&dest-file ;asma-assemble-file JSR2
BRK
(
If an error has occurred, BRK here, otherwise continue. (The error
message will already have been printed to the Console in
asma-assemble-file.)
)
;asma/error LDA2 #0000 EQU2 JMP BRK
(
Load the output ROM over the currently running program, almost as if
we loaded the ROM with uxnemu directly!
It's not a totally pristine environment, as File/load doesn't zero out
memory beyond the end of the file. So if the assembled program assumes
that all memory above it is zero, it may misbehave.
Asma itself doesn't use the zero page, but this example code writes a
DEO2 instruction to 0x00ff. In order to execute File/load and have the
CPU continue at memory location 0x0100, we write the final DEO2
instruction there and jump there as our final act.
)
;&dest-file .File/name DEO2
#0000 .File/offset DEO2
#ff00 .File/length DEO2
#0100 .File/load
LIT DEO2 #00ff STA
#00ff JMP2
&source-file
"projects/demos/piano.usm 00
@ -21,13 +66,14 @@
%asma-IF-ERROR { ;asma/error LDA2 ORA }
%asma-LOG { #01 }
(
#00 first pass output
#01 second pass output
#02 current token
#04 label dump at end
asma-LOG is a log-level parameter for helping to debug stuff.
It's value is the bitwise OR of all the following output types:
#01 prints the number of lines in the source code,
#02 prints tokens as they are processed, and
#04 dumps all defined labels at end.
)
%asma-DEO2 { asma-LOG NEQ JMP DEO2k POP POP2 }
%asma-DEO { asma-LOG NEQ JMP DEOk POP2 }
%asma-DEO2 { asma-LOG AND #00 EQU JMP DEO2k POP POP2 }
%asma-DEO { asma-LOG AND #00 EQU JMP DEOk POP2 }
(
Asma's public interface.
@ -70,6 +116,7 @@
#20 .Console/char DEO
;asma/orig-token LDA2 .Console/string DEO2
;&line .Console/string DEO2
( FIXME it would be nicer if line numbers were in decimal )
;asma/line LDA2 .Console/short DEO2
#2e .Console/char DEO
#0a .Console/char DEO
@ -78,8 +125,9 @@
&line 20 "on 20 "line 20 00
@asma-print-linecount ( -- )
;asma/line LDA2 .Console/short #04 asma-DEO2
;&lines .Console/string #04 asma-DEO2
( FIXME it would be nicer if line numbers were in decimal )
;asma/line LDA2 .Console/short #01 asma-DEO2
;&lines .Console/string #01 asma-DEO2
JMP2r
&lines [ 20 "lines 20 "in 20 "total. 0a 00 ]