From 1703d41b68004e548a5e6abd0901fc1b4b8f0a47 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jo=C3=A3o=20Magalh=C3=A3es?= <joamag@gmail.com>
Date: Sun, 19 Jun 2022 01:13:50 +0100
Subject: [PATCH] feat: new loading of fonts
---
src/chip8_neo.rs | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/src/chip8_neo.rs b/src/chip8_neo.rs
index d0a0d15..8c9e62a 100644
--- a/src/chip8_neo.rs
+++ b/src/chip8_neo.rs
@@ -112,7 +112,7 @@ impl Chip8Neo {
0x4000 => self.pc += if self.regs[x] != byte { 2 } else { 0 },
0x5000 => self.pc += if self.regs[x] == self.regs[y] { 2 } else { 0 },
0x6000 => self.regs[x] = byte,
- 0x7000 => self.regs[x] += byte,
+ 0x7000 => self.regs[x] = self.regs[x].wrapping_add(byte),
0x8000 => match nibble {
0x0 => self.regs[x] = self.regs[y],
0x1 => self.regs[x] |= self.regs[y],
@@ -125,7 +125,7 @@ impl Chip8Neo {
}
0x5 => {
self.regs[0xf] = (self.regs[x] >= self.regs[y]) as u8;
- self.regs[x] = self.regs[x] - self.regs[y];
+ self.regs[x] = self.regs[x].saturating_sub(self.regs[y]);
}
0x6 => {
self.regs[0xf] = self.regs[x] & 0x01;
@@ -133,7 +133,7 @@ impl Chip8Neo {
}
0x7 => {
self.regs[0xf] = (self.regs[y] >= self.regs[x]) as u8;
- self.regs[x] = self.regs[y] - self.regs[x];
+ self.regs[x] = self.regs[y].saturating_sub(self.regs[x]);
}
0xe => {
self.regs[0xf] = (self.regs[x] & 0x80) >> 7;
@@ -156,15 +156,16 @@ impl Chip8Neo {
0x07 => self.regs[x] = self.dt,
0x15 => self.dt = self.regs[x],
0x18 => self.st = self.regs[x],
+ 0x29 => self.i = self.regs[x] as u16 * 5,
0x33 => {
self.ram[self.i as usize] = self.regs[x] / 100;
self.ram[self.i as usize + 1] = (self.regs[x] / 10) % 10;
self.ram[self.i as usize + 2] = self.regs[x] % 10;
}
- 0x55 => self.ram[self.i as usize..(self.i as usize + x)]
- .clone_from_slice(&self.regs[0..x]),
- 0x65 => self.regs[0..x]
- .clone_from_slice(&self.ram[self.i as usize..(self.i as usize + x)]),
+ 0x55 => self.ram[self.i as usize..self.i as usize + x + 1]
+ .clone_from_slice(&self.regs[0..x + 1]),
+ 0x65 => self.regs[0..x + 1]
+ .clone_from_slice(&self.ram[self.i as usize..self.i as usize + x + 1]),
_ => println!(
"unimplemented instruction 0xf000, instruction 0x{:04x}",
instruction
--
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