A voice starts pointed at its track, without code to point it
There is no assembler bug. I reported one and was wrong. A label written in the Data Segment does come out as its address, two bytes, most significant first - implemented in populateOutputBuffers, documented in the Assembler Manual, and correct. What misled me was the test I checked it with: the label was the first thing in an unbased Data Segment, so its address really was 0x0000, and I read the right answer as an unfilled placeholder. So Play was doing at run time what the assembler had already offered to do at assembly time. The voice records now carry their track labels directly, which is exactly the shape LDD reads, and nothing relocates on this machine so the address written is the address it will have. That takes out startVoice, its four call sites, and the eight SETDs that fed them: 450 bytes to 379, and the initial state of a voice is now something you can read rather than something you have to follow the code to work out. The comment claiming otherwise is gone from Play.asm, and the same change is made in fourVoiceTest. The music is unchanged - bar by bar the render matches to within one per cent, which is the program loading a shade sooner because it is smaller. Ten recordings moved for the same reason: 446 to 379, and nothing else. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW
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co-authored by
Claude Opus 5
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@@ -43,13 +43,6 @@ start:
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OUTA 0x51
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SIF
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SETD.1 Voice0
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SETD.0 Track0
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CALL startVoice
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SETD.1 Voice1
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SETD.0 Track1
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CALL startVoice
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; Twelve ticks. B survives the calls below, because a CALL saves it.
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INIB 0d12
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tickLoop:
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@@ -110,14 +103,6 @@ stepVoice:
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stepDone:
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RET
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; DP1 a voice, DP0 its track. A count of one, so the first pass fetches the first event.
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startVoice:
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STD.0.1
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DPUP.1 0d2
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INIA 0d1
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STA.1
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RET
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; Held at full and released quickly, so a note lasts exactly its ticks and the boundary
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; between two of them is something a counter can find.
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setUpChannel:
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@@ -157,10 +142,13 @@ tick:
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#Data
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; Cursor high, cursor low, count, spare. A label written here comes out as its address, most
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; significant first, which is the shape LDD reads - so a voice starts pointed at its track
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; with no code at all. The count starts at one so the first pass runs it out and fetches.
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Voice0:
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0x00 0x00 0x00 0x00
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Track0 0d1 0d0
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Voice1:
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0x00 0x00 0x00 0x00
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Track1 0d1 0d0
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ThisChannel:
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0x00
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