First pass at getting Acadia running under bochs.

- Create a bochs build script.
- Properly configure COM1

.bochsrc

@@ -0,0 +1,12 @@
+megs: 1024
+ata0-master: type=disk, path=builddbg/disk.img, mode=flat, cylinders=512, heads=16, spt=50
+display_library: sdl2, options="gui_debug"
+boot: disk
+com1: enabled=1, mode=file, dev=serial.out, baud=9600, parity=none, bits=8, stopbits=1
+cpu: model=corei7_sandy_bridge_2600k
+pci: enabled=1, chipset=i440bx
+log: bochs.log
+# TODO: Make this portable, by building bochs locally.
+romimage: file=/home/drew/opt/bochs/share/bochs/BIOS-bochs-latest
+vgaromimage: file=/home/drew/opt/bochs/share/bochs/VGABIOS-lgpl-latest.bin
+vga: extension=vbe

.gitignore

@@ -4,6 +4,9 @@ __pycache__/
 .ccls-cache/
 compile_commands.json
 
+bochs.log
+serial.out
+
 sysroot/bin
 sysroot/usr
 sysroot/.crates.toml

scripts/bochs.sh

@@ -0,0 +1,19 @@
+#! /bin/bash
+
+set -e
+
+DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+
+BUILD_DIR="${DIR}/../builddbg"
+
+bash ${DIR}/build.sh
+sudo sh ${DIR}/build_image.sh ${BUILD_DIR}/disk.img
+
+BOCHS_ARGS=
+if [[ $1 == "debug" ]]; then
+  BOCHS_ARGS+="--dbg"
+fi
+
+# TODO Make this portable, build bochs as a part of toolchain?
+~/opt/bochs/bin/bochs
+

scripts/build.sh

@@ -0,0 +1,32 @@
+#! /bin/bash
+
+set -e
+
+DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+
+echo $DIR
+
+BUILD_DIR="${DIR}/../builddbg"
+
+pushd $BUILD_DIR 
+ninja 
+ninja install
+
+CARGO_USR_ROOT="${DIR}/../sysroot/usr/"
+CARGO_SYS_ROOT="${DIR}/../sysroot/"
+
+# Need to pushd so rustup gets the toolchain from rust/rust_toolchain.toml
+pushd "${DIR}/../rust"
+
+for BIN in ${DIR}/../rust/usr/*/; do
+  cargo install --force --path "${BIN}" --root $CARGO_USR_ROOT
+done
+
+for BIN in ${DIR}/../rust/sys/*/; do
+  cargo install --all-features --force --path "${BIN}" --root $CARGO_SYS_ROOT
+done
+popd
+
+popd
+
+

scripts/build_image.sh

@@ -1,7 +1,11 @@
-#!/us
+#! /bin/bash
 
 set -e
 
+SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+REPO_ROOT="$SCRIPT_DIR/.."
+BUILD_DIR="$REPO_ROOT/builddbg"
+
 if [[ $# -ne 1 ]]; then
   echo "Must specify disk image name."
 fi
@@ -15,11 +19,14 @@ if [ -z "$dev" ]; then
 fi
 echo "Loopback device: ${dev}"
 
+EFI_DIR="$BUILD_DIR/efi"
+SYSROOT="$BUILD_DIR/sysroot"
+
 cleanup() {
-  umount efi
+  umount $EFI_DIR
-  rm -rf efi
+  rm -rf $EFI_DIR
-  umount sysroot
+  umount $SYSROOT
-  rm -rf sysroot
+  rm -rf $SYSROOT
   losetup -d $dev
 }
 trap cleanup EXIT
@@ -30,22 +37,23 @@ mke2fs "${dev}p2"
 
 limine bios-install "${dev}"
 
-mkdir -p efi/
-mount "${dev}p1" efi/
 
-mkdir -p efi/EFI/BOOT
+mkdir -p $EFI_DIR
-cp /usr/share/limine/BOOTX64.EFI efi/EFI/BOOT
+mount "${dev}p1" $EFI_DIR
-cp /usr/share/limine/limine-bios.sys efi/
-cp ../zion/boot/limine.conf efi/
-cp zion/zion efi/
-mkdir -p efi/sys
-cp ../sysroot/bin/yellowstone efi/sys/yellowstone
-cp ../sysroot/bin/denali efi/sys/denali
-cp ../sysroot/bin/victoriafalls efi/sys/victoriafalls
 
-mkdir -p sysroot
+mkdir -p $EFI_DIR/EFI/BOOT
-mount "${dev}p2" sysroot/
+cp /usr/share/limine/BOOTX64.EFI $EFI_DIR/EFI/BOOT
-rsync -a ../sysroot .
+cp /usr/share/limine/limine-bios.sys $EFI_DIR
-ls sysroot/
+cp $REPO_ROOT/zion/boot/limine.conf $EFI_DIR/
+cp $BUILD_DIR/zion/zion $EFI_DIR/
+mkdir -p $EFI_DIR/sys
+cp $REPO_ROOT/sysroot/bin/yellowstone $EFI_DIR/sys/yellowstone
+cp $REPO_ROOT/sysroot/bin/denali $EFI_DIR/sys/denali
+cp $REPO_ROOT/sysroot/bin/victoriafalls $EFI_DIR/sys/victoriafalls
+
+mkdir -p $SYSROOT
+mount "${dev}p2" $SYSROOT
+rsync -a "$REPO_ROOT/sysroot" $BUILD_DIR
+ls $SYSROOT
 
 chown drew:drew $1

scripts/qemu.sh

@@ -8,26 +8,9 @@ echo $DIR
 
 BUILD_DIR="${DIR}/../builddbg"
 
-pushd $BUILD_DIR 
-ninja 
-ninja install
 
-CARGO_USR_ROOT="${DIR}/../sysroot/usr/"
+bash ${DIR}/build.sh
-CARGO_SYS_ROOT="${DIR}/../sysroot/"
+sudo sh ${DIR}/build_image.sh ${BUILD_DIR}/disk.img
-
-# Need to pushd so rustup gets the toolchain from rust/rust_toolchain.toml
-pushd "${DIR}/../rust"
-
-for BIN in ${DIR}/../rust/usr/*/; do
-  cargo install --force --path "${BIN}" --root $CARGO_USR_ROOT
-done
-
-for BIN in ${DIR}/../rust/sys/*/; do
-  cargo install --all-features --force --path "${BIN}" --root $CARGO_SYS_ROOT
-done
-popd
-
-sudo sh ${DIR}/build_image.sh disk.img
 
 QEMU_ARGS=
 if [[ $1 == "debug" ]]; then
@@ -35,7 +18,7 @@ if [[ $1 == "debug" ]]; then
 fi
 
 # Use machine q35 to access PCI devices.
-qemu-system-x86_64 -machine q35 -d guest_errors -m 1G -serial stdio -hda disk.img ${QEMU_ARGS} -device nec-usb-xhci,id=xhci -device usb-kbd,bus=xhci.0
+qemu-system-x86_64 -machine q35 -d guest_errors -m 1G -serial stdio -hda ${BUILD_DIR}/disk.img ${QEMU_ARGS} -device nec-usb-xhci,id=xhci -device usb-kbd,bus=xhci.0
 popd
 
 # Extra options to add to this script in the future.

zion/debug/debug.cpp

@@ -39,3 +39,52 @@ void dbgln(const glcr::StringView& str) {
   dbg(str);
   dbg("\n");
 }
+
+namespace {
+
+// Helper function to write a byte to a specified COM1 register offset
+void write_serial_port(uint16_t offset, uint8_t value) {
+  outb(COM1 + offset, value);
+}
+
+// Helper function to read a byte from a specified COM1 register offset
+uint8_t read_serial_port(uint16_t offset) { return inb(COM1 + offset); }
+
+}  // namespace
+
+namespace serial {
+
+// Function to initialize the serial port with a given baud rate
+void initialize(uint32_t baud_rate) {
+  // Disable interrupts
+  write_serial_port(1, 0x00);
+
+  // Enable DLAB (Divisor Latch Access Bit) in Line Control Register (LCR)
+  write_serial_port(3, read_serial_port(3) | 0x80);
+
+  // Calculate the divisor
+  // Baud rate = 115200 / divisor (approximately)
+  uint16_t divisor = 115200 / baud_rate;
+
+  // Set the low byte of the divisor
+  write_serial_port(0, divisor & 0xFF);
+
+  // Set the high byte of the divisor
+  write_serial_port(1, (divisor >> 8) & 0xFF);
+
+  // Clear DLAB and set data bits, stop bits, and parity
+  // 8 data bits, 1 stop bit, no parity
+  write_serial_port(3, 0x03);  // 00000011b
+
+  // Enable FIFO, clear buffers, set trigger level (e.g., 1 byte)
+  write_serial_port(2, 0xC7);  // 11000111b
+
+  // Enable IRQs (optional, for interrupt-driven communication)
+  // write_serial_port(1, 0x01);
+
+  // Set Modem Control Register (MCR)
+  // Enable RTS, DTR, OUT1, OUT2, loopback off, IRQs enabled
+  write_serial_port(4, 0x0B);  // 00001011b
+}
+
+}  // namespace serial

zion/debug/debug.h

@@ -37,3 +37,9 @@ void panic(const char* str, Args&&... args) {
 #define UNREACHABLE                                                  \
   panic("Unreachable {}, {}", glcr::StringView(__FILE__), __LINE__); \
   __builtin_unreachable();
+
+namespace serial {
+
+void initialize(uint32_t baud_rate);
+
+}

zion/zion.cpp

@@ -20,6 +20,7 @@
 #include "syscall/syscall.h"
 
 extern "C" void zion() {
+  serial::initialize(9600);
   dbgln("[boot] Init GDT & IDT.");
   InitGdt();
   InitIdt();