~shiny/gbcap: Fix a couple of off-by-one errors in the OUTPUT_DONE state

591b0ab82aa48e18a2c30fc297801b3666da6520 — Thomas Spurden 3 years ago 3869284

Fix a couple of off-by-one errors in the OUTPUT_DONE state

Would "leak" some lines on each frame and so eventually overflow the
buffer.

patch browse .tar.gz

1 files changed, 3 insertions(+), 3 deletions(-)

M compress.py

M compress.py => compress.py +3 -3

@@ 304,15 304,15 @@ class CompressFrames(Module):
                     NextValue(full_lines, full_lines + 1)
                 )
             ).Else(
-                If(line_within_frame == frame_height - 1,
+                If(last_line,
                     # Been keeping around MAX_Y_OFFSET extra lines from the previous
                     # frame but now it's the last line of the frame so can drop them
                     If(write_port.we,
                         NextValue(full_lines, full_lines - MAX_Y_OFFSET)
                     ).Else(
-                        NextValue(full_lines, full_lines - MAX_Y_OFFSET + 1)
+                        NextValue(full_lines, full_lines - MAX_Y_OFFSET - 1)
                     )
-                ).Elif(line_within_frame > MAX_Y_OFFSET,
+                ).Elif(line_within_frame >= MAX_Y_OFFSET,
                     # Keep MAX_Y_OFFSET extra lines from the previous frame for
                     # prediction
                     If(~write_port.we,