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changeset 1110:d1eed3b1121c

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Fix a couple of timing regressions in Z80 core
author Michael Pavone <pavone@retrodev.com>
date Wed, 14 Dec 2016 23:27:42 -0800
parents 4bc27caa6e20
children 2eb54e24914e
files z80_to_x86.c
diffstat 1 files changed, 7 insertions(+), 2 deletions(-) [+]
line wrap: on
line diff
--- a/z80_to_x86.c	Wed Dec 14 23:26:12 2016 -0800
+++ b/z80_to_x86.c	Wed Dec 14 23:27:42 2016 -0800
@@ -363,7 +363,7 @@
 			break;
 		case Z80_IX_DISPLACE:
 		case Z80_IY_DISPLACE:
-			num_cycles = 8; //3 for displacement, 5 for address addition
+			num_cycles += 8; //3 for displacement, 5 for address addition
 			break;
 		}
 		cycles(&opts->gen, num_cycles);
@@ -1417,11 +1417,16 @@
 		cycles(&opts->gen, num_cycles);
 		mov_irdisp(code, 0, opts->gen.context_reg, offsetof(z80_context, iff1), SZ_B);
 		mov_irdisp(code, 0, opts->gen.context_reg, offsetof(z80_context, iff2), SZ_B);
+		//turn cycles remaining into current cycle
+		neg_r(code, opts->gen.cycles, SZ_D);
 		add_rdispr(code, opts->gen.context_reg, offsetof(z80_context, target_cycle), opts->gen.cycles, SZ_D);
+		//set interrupt cycle to never and fetch the new target cycle from sync_cycle
 		mov_rdispr(code, opts->gen.context_reg, offsetof(z80_context, sync_cycle), opts->gen.scratch1, SZ_D);
 		mov_irdisp(code, 0xFFFFFFFF, opts->gen.context_reg, offsetof(z80_context, int_cycle), SZ_D);
 		mov_rrdisp(code, opts->gen.scratch1, opts->gen.context_reg, offsetof(z80_context, target_cycle), SZ_D);
-		sub_rr(code, opts->gen.scratch1, opts->gen.cycles, SZ_D);
+		//turn current cycle back into cycles remaining
+		neg_r(code, opts->gen.cycles, SZ_D);
+		add_rr(code, opts->gen.scratch1, opts->gen.cycles, SZ_D);
 		break;
 	case Z80_EI:
 		cycles(&opts->gen, num_cycles);