mirror of https://git.sr.ht/~rabbits/uxn
103 lines
2.9 KiB
Tal
103 lines
2.9 KiB
Tal
( devices )
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|00 @System [ &vector $2 &wst $1 &rst $1 &pad $4 &r $2 &g $2 &b $2 &debug $1 &halt $1 ]
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|10 @Console [ &vector $2 &read $1 &pad $5 &write $1 &error $1 ]
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|a0 @File [ &vector $2 &success $2 &stat $2 &delete $1 &append $1 &name $2 &length $2 &read $2 &write $2 ]
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( vectors )
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|0100 @reset
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(
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Set the log level for helping to debug stuff.
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Its value is the bitwise OR of all the following output types:
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#01 prints the number of lines in the source code,
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#04 dumps all defined labels at end, and
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#08 prints the heap usage.
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)
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#0d ;asma/log-level STA
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;asma-heap ;heap STA2
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(
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Assemble the source code into an output ROM file.
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If all you want is to use asma.tal to assemble files, insert a BRK
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after this statement.
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)
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;&source-file ;&dest-file ;asma-assemble-file JSR2
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(
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If an error has occurred, BRK here, otherwise continue. (The error
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message will already have been printed to the Console in
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asma-assemble-file.)
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)
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;asma/error LDA2 #0000 EQU2 JMP BRK
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(
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Load the output ROM over the currently running program, almost as if
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we loaded the ROM with uxnemu directly!
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It's not a totally pristine environment, as File/read doesn't zero out
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memory beyond the end of the file. So if the assembled program assumes
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that all memory above it is zero, it may misbehave.
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Asma itself doesn't use the zero page, but this example code writes a
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DEO2 instruction to 0x00ff. In order to execute File/read and have the
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CPU continue at memory location 0x0100, we write the final DEO2
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instruction there and jump there as our final act.
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Just in case the assembled code is zero-length (which can occur when
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assembling an empty source file), we write a BRK to the reset vector so
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that will prevent an infinite loop.
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)
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;&dest-file .File/name DEO2
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#ff00 .File/length DEO2
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#0100 .File/read
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LIT DEO2 #00ff STA
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LIT BRK #0100 STA
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#00ff JMP2
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&source-file
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"projects/examples/demos/piano.tal 00
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&dest-file
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"bin/asma-boot.rom 00
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~projects/library/asma.tal
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(
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Heap, a large temporary area for keeping track of labels. More complex
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programs need more of this space. If there's insufficient space then the
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assembly process will fail, but having extra space above what the most
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complex program needs provides no benefit.
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This heap, and the buffers below, are free to be used to hold temporary
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data between assembly runs, and do not need to be initialized with any
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particular contents to use the assembler.
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)
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@asma-heap
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|e000 &end
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(
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Buffer for use with loading source code.
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The minimum size is the length of the longest token plus one, which is
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0x21 to keep the same capability of the C assembler.
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Larger sizes are more efficient, provided there is enough
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heap space to keep track of all the labels.
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)
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@asma-read-buffer
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|f800 &end
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(
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Buffer for use with writing output.
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The minimum size is 1, and larger sizes are more efficient.
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)
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@asma-write-buffer
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|ffff &end
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