From 10d591ee52c22c7ae675f7ab78328056fbc93389 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jo=C3=A3o=20Magalh=C3=A3es?= <joamag@gmail.com>
Date: Sat, 25 Jun 2022 17:37:40 +0100
Subject: [PATCH] feat: new instructions
---
src/cpu.rs | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)
diff --git a/src/cpu.rs b/src/cpu.rs
index 7034b441..6a622181 100644
--- a/src/cpu.rs
+++ b/src/cpu.rs
@@ -230,15 +230,22 @@ fn ld_mu16_sp(cpu: &mut Cpu) {
}
fn add_hl_bc(cpu: &mut Cpu) {
- let value = cpu.hl() as u32 + cpu.bc() as u32;
-
- cpu.set_sub(false);
- cpu.set_carry(value & 0x1000 == 0x1000);
- cpu.set_half_carry((value & 0xff) == 0xff); //@todo I'm not sure about this one
-
- cpu.set_hl(value as u16);
+ let value = add_u16_u16(cpu, cpu.hl(), cpu.bc());
+ cpu.set_hl(value);
}
fn ld_sp_u16(cpu: &mut Cpu) {
cpu.sp = cpu.read_u16();
}
+
+fn add_u16_u16(cpu: &mut Cpu, first: u16, second: u16) -> u16 {
+ let first = first as u32;
+ let second = second as u32;
+ let value = first.wrapping_add(second);
+
+ cpu.set_sub(false);
+ cpu.set_carry(value & 0x1000 == 0x1000);
+ cpu.set_half_carry((first ^ second ^ value) & 0x1000 == 0x1000);
+
+ value as u16
+}
--
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