From 21ce4632e4c0ae6b08d6bbff1116fbdebece6465 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jo=C3=A3o=20Magalh=C3=A3es?= <joamag@gmail.com>
Date: Sun, 16 Apr 2023 02:19:33 +0100
Subject: [PATCH] feat: added allow slave flag
---
src/devices/printer.rs | 4 ++++
src/devices/stdout.rs | 4 ++++
src/serial.rs | 22 +++++++++++++++++-----
3 files changed, 25 insertions(+), 5 deletions(-)
diff --git a/src/devices/printer.rs b/src/devices/printer.rs
index a9ede2b1..c262fc43 100644
--- a/src/devices/printer.rs
+++ b/src/devices/printer.rs
@@ -246,6 +246,10 @@ impl SerialDevice for PrinterDevice {
self.state = PrinterState::from_u8(self.state as u8 + 1);
}
}
+
+ fn allow_slave(&self) -> bool {
+ false
+ }
}
impl Default for PrinterDevice {
diff --git a/src/devices/stdout.rs b/src/devices/stdout.rs
index f9a7ad4f..a2f7528c 100644
--- a/src/devices/stdout.rs
+++ b/src/devices/stdout.rs
@@ -23,6 +23,10 @@ impl SerialDevice for StdoutDevice {
stdout().flush().unwrap();
}
}
+
+ fn allow_slave(&self) -> bool {
+ false
+ }
}
impl Default for StdoutDevice {
diff --git a/src/serial.rs b/src/serial.rs
index 5726ac29..6e79b68f 100644
--- a/src/serial.rs
+++ b/src/serial.rs
@@ -3,6 +3,11 @@ use crate::warnln;
pub trait SerialDevice {
fn send(&mut self) -> u8;
fn receive(&mut self, byte: u8);
+
+ /// Whether the serial device "driver" supports slave mode
+ /// simulating an external clock source. Or if instead the
+ /// clock should always be generated by the running device.
+ fn allow_slave(&self) -> bool;
}
pub struct Serial {
@@ -89,15 +94,18 @@ impl Serial {
self.clock_speed = value & 0x02 == 0x02;
self.transferring = value & 0x80 == 0x80;
- // @TODO: THIS SEEMS LIKE A HACK, we'll need to check with
- // the device driver how to handle no communication and receive
- // we must simulate no cable communication
- if self.transferring && !self.shift_clock {
+ // in case the clock is meant to be set by the attached device
+ // and the current Game Boy is meant to be running in slave mode
+ // then checks if the attached device "driver" allows clock set
+ // by external device and if not then ignores the transfer request
+ // by immediately disabling the transferring flag
+ if !self.shift_clock && !self.device.allow_slave() {
self.transferring = false;
}
+
// in case a transfer of byte has been requested and
// this is the then we need to start the transfer setup
- else if self.transferring {
+ if self.transferring {
// @TODO: if the GBC mode exists there should
// be special check logic here
//self.length = if self.gb.is_cgb() && self.clock_speed { 16 } else { 512 };
@@ -189,6 +197,10 @@ impl SerialDevice for NullDevice {
}
fn receive(&mut self, _: u8) {}
+
+ fn allow_slave(&self) -> bool {
+ false
+ }
}
impl Default for NullDevice {
--
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