From e6f0c80ca0a5cdac7d9a2b0dadde1d200712c66d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jo=C3=A3o=20Magalh=C3=A3es?= <joamag@gmail.com>
Date: Wed, 29 Jun 2022 10:46:13 +0100
Subject: [PATCH] feat: new jump opcode
---
src/cpu.rs | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/src/cpu.rs b/src/cpu.rs
index 02f7d692..6ea093ba 100644
--- a/src/cpu.rs
+++ b/src/cpu.rs
@@ -46,7 +46,7 @@ pub const INSTRUCTIONS: [(fn(&mut Cpu), u8, &'static str); 256] = [
(nop, 4, "! UNIMP !"),
(nop, 4, "! UNIMP !"),
(nop, 4, "! UNIMP !"),
- (nop, 4, "! UNIMP !"),
+ (jr_z_i8, 8, "JR Z, i8"),
(nop, 4, "! UNIMP !"),
(nop, 4, "! UNIMP !"),
(nop, 4, "! UNIMP !"),
@@ -816,6 +816,17 @@ fn inc_hl(cpu: &mut Cpu) {
cpu.set_hl(cpu.hl().wrapping_add(1));
}
+fn jr_z_i8(cpu: &mut Cpu) {
+ let byte = cpu.read_u8() as i8;
+
+ if !cpu.get_zero() {
+ return;
+ }
+
+ cpu.pc = (cpu.pc as i16).wrapping_add(byte as i16) as u16;
+ cpu.ticks = cpu.ticks.wrapping_add(4);
+}
+
fn ld_sp_u16(cpu: &mut Cpu) {
cpu.sp = cpu.read_u16();
}
--
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