Fix display window, HBLANK timing, sprite visibility and STRLONG#7
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thbreidenbach wants to merge 1 commit intoendofexclusive:masterfrom
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Fix display window, HBLANK timing, sprite visibility and STRLONG#7thbreidenbach wants to merge 1 commit intoendofexclusive:masterfrom
thbreidenbach wants to merge 1 commit intoendofexclusive:masterfrom
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Correct multiple display issues by comparing against the amiga_replacement_project Denise implementation: - Fix HBLANK start/stop constants (was 3/85, now $013/$061) to match real Denise/Minimig timing. Fixes display shifted left with right side cut off. - Add STRLONG (long-line) support for interlaced modes. The beam counter now holds for one extra CLK7 cycle when STRLONG is received. - Improve display window (DIW) pipeline: add vertical window tracking (vwin, set by BPL1DAT writes, cleared at HPOS $13), multi-stage horizontal window (hwin0/hwin1/hwin2) for proper pipeline alignment. - Reset HPOS to 2 at line start (was $1FE), matching real Denise. - Mask bitplane pixels to zero outside DIW directly in stage E bplbus generation, separately for lores and hires modes. - Allow sprites to display outside the display window (border region). Real Amiga Denise draws sprites independently of DIW — the mouse pointer, status bar sprites and demo effects rely on this. The previous code killed all sprites outside DIW. - In stage G priority output, only blank playfield colors (bit 4 = 0) outside DIW; preserve sprite colors (bit 4 = 1, registers 16-31). Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Summary
Background
Analysis was performed by comparing this implementation against the amiga_replacement_project Verilog Denise implementation, which correctly handles all of the above cases. The key architectural insight is that in real Denise hardware, the display window only gates bitplane output — sprites operate on an independent path and must remain visible in border/overscan areas.
Test plan
🤖 Generated with Claude Code