floppy: Gently de-jitter/precomp WDATA line

This can be enough to handle heavily-precompensated marginal write signals.
keirf · Jan 10, 2024 · 359d964 · 359d964
1 parent 69e2c54
commit 359d964
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/src/floppy_generic.c b/src/floppy_generic.c
@@ -686,6 +686,8 @@ static void IRQ_wdata_dma(void)
             if (!(bc_prod&31))
                 bc_buf[((bc_prod-1) / 32) & bc_bufmask] = htobe32(bc_dat);
         }
+        curr += cell >> 1; /* remove the 1/2-cell bias */
+        prev -= curr >> 3; /* de-jitter/precomp: carry 1/8 of phase error */
         bc_dat = (bc_dat << 1) | 1;
         bc_prod++;
         switch (sync) {