Record networking and DMA development progress

Add the current OS source tree, build scripts, system image layout, and development notes covering DMA page allocation, e1000 bring-up, net API dispatch, and DHCP work in progress.

CODE/mouse/MAKEFILE

@@ -0,0 +1,25 @@
+CC := clang
+LD := ld.lld
+
+ROOT := ../..
+OUT := $(ROOT)/SYSTEM/system/deshab64/mouse/mouseInit.elf
+
+CFLAGS := -target x86_64-unknown-none -std=c11 -ffreestanding -fno-builtin -fno-stack-protector -fpie -mno-red-zone -mno-sse -mno-sse2 -mno-mmx -msoft-float -m64 -Wall -Wextra -I../UTSM/include -O2
+LDFLAGS := -nostdlib -static -pie -z max-page-size=0x1000 -T linker.ld
+
+C_SOURCES := main.c
+OBJECTS := $(C_SOURCES:.c=.o)
+
+.PHONY: all clean
+
+all: $(OUT)
+
+$(OUT): $(OBJECTS) linker.ld
+	@if not exist "$(ROOT)\SYSTEM\system\deshab64\mouse" mkdir "$(ROOT)\SYSTEM\system\deshab64\mouse"
+	$(LD) $(LDFLAGS) -o $@ $(OBJECTS)
+
+%.o: %.c
+	$(CC) $(CFLAGS) -c $< -o $@
+
+clean:
+	powershell -NoProfile -Command "Get-ChildItem -Path . -Recurse -Filter *.o | Remove-Item -Force; if (Test-Path '$(OUT)') { Remove-Item '$(OUT)' -Force }"

CODE/mouse/linker.ld

@@ -0,0 +1,16 @@
+ENTRY(dsk_entry)
+
+PHDRS
+{
+    text   PT_LOAD FLAGS(5);
+    rodata PT_LOAD FLAGS(4);
+    data   PT_LOAD FLAGS(6);
+}
+
+SECTIONS
+{
+    . = 0x1000;
+    .text : ALIGN(4K) { *(.text*) } :text
+    .rodata : ALIGN(4K) { *(.rodata*) } :rodata
+    .data : ALIGN(4K) { *(.data*) *(COMMON) *(.bss*) } :data
+}

CODE/mouse/main.c

@@ -0,0 +1,38 @@
+/* mouseInit — safe mouse initializer stub
+ * DSK-owned system component initializer.
+ * Current version must never block or crash first boot.
+ */
+
+#include "../UTSM/include/utsm/dsk.h"
+
+typedef unsigned char u8;
+typedef unsigned short u16;
+typedef unsigned int u32;
+
+#define COM1 0x3F8
+#define PS2_STATUS 0x64
+
+static inline void outb(u16 port, u8 value) { __asm__ volatile("outb %0,%1"::"a"(value),"Nd"(port)); }
+static inline u8 inb(u16 port) { u8 v; __asm__ volatile("inb %1,%0":"=a"(v):"Nd"(port)); return v; }
+
+static void sputc(char c) {
+    for (u32 i=0;i<10000;i++) if (inb(COM1+5)&0x20) break;
+    outb(COM1,(u8)c);
+}
+static void swrite(const char *s) { while(*s){ if(*s=='\n') sputc('\r'); sputc(*s++);} }
+static void logl(const char *s) { swrite(s); swrite("\n"); }
+
+__attribute__((visibility("default")))
+void dsk_entry(const dsk_boot_context *ctx) {
+    (void)ctx;
+    logl("[mouseInit] boot");
+
+    /* Safe first version: do not touch PS/2 controller command path yet.
+       The previous implementation could block/reboot on some firmware states.
+       Full IRQ12 + packet decoding will be implemented as a later input driver. */
+    u8 status = inb(PS2_STATUS);
+    (void)status;
+
+    logl("[mouseInit] safe init complete");
+    return;
+}

CODE/mouse/readme

@@ -0,0 +1,41 @@
+# mouseInit 鼠标初始化器
+
+`CODE/mouse` 生成早期鼠标初始化 ELF：
+
+```text
+CODE/mouse -> SYSTEM/system/deshab64/mouse/mouseInit.elf
+```
+
+## 目标
+
+`mouseInit.elf` 是 DSK 直接调度的系统输入初始化器，不属于 FirstInit 用户向导。DSK 在检测到首次启动后先加载并调用它，初始化完成后返回 DSK，再由 DSK 启动 FirstInit 用户设置向导。
+
+第一版职责：
+
+1. 初始化 PS/2 Controller 的辅助设备通道（mouse / AUX）。
+2. 开启 IRQ12 配置位。
+3. 向鼠标发送默认配置 `0xF6`。
+4. 启用数据报告 `0xF4`。
+5. 输出串口日志并返回 DSK。
+
+## 当前限制
+
+- 当前只做 PS/2 鼠标初始化，不消费鼠标包。
+- 鼠标 IRQ12 的实际数据读取应由后续 DKM 输入驱动或 DSK 输入子系统接管。
+- USB 鼠标需要 xHCI/HID 支持，暂不在第一版范围。
+
+## 构建
+
+```powershell
+cd CODE\mouse
+make -f MAKEFILE CC=clang LD=ld.lld
+```
+
+## 启动链路
+
+```text
+DSK 检测 firstInit=0
+  -> 加载并调用 mouseInit.elf
+  -> mouseInit 初始化 PS/2 鼠标后返回
+  -> DSK 继续加载 FirstInit.elf
+```