add A1-Input

A1-Input/Makefile

@@ -0,0 +1,20 @@
+CC = riscv64-unknown-elf-gcc
+CFLAGS = -nostdlib -fno-builtin -mcmodel=medany -march=rv32ima -mabi=ilp32
+
+QEMU = qemu-system-riscv32
+QFLAGS = -nographic -smp 4 -machine virt -bios none
+
+OBJDUMP = riscv64-unknown-elf-objdump
+
+all: os.elf
+
+os.elf: start.s os.c
+	$(CC) $(CFLAGS) -T os.ld -o os.elf $^
+
+qemu: $(TARGET)
+	@qemu-system-riscv32 -M ? | grep virt >/dev/null || exit
+	@echo "Press Ctrl-A and then X to exit QEMU"
+	$(QEMU) $(QFLAGS) -kernel os.elf
+
+clean:
+	rm -f *.elf

A1-Input/linux.md

@@ -0,0 +1,13 @@
+
+
+```
+guest@localhost:~/sp/10-riscv/03-mini-riscv-os/01-HelloOs$ ls
+01-HelloOs--嵌入式RISC-V輸出入程式.md  Makefile  os.c  os.ld  run.md  start.s
+guest@localhost:~/sp/10-riscv/03-mini-riscv-os/01-HelloOs$ make 
+riscv64-unknown-elf-gcc -nostdlib -fno-builtin -mcmodel=medany -march=rv32ima -mabi=ilp32 -T os.ld -o os.elf start.s os.c
+guest@localhost:~/sp/10-riscv/03-mini-riscv-os/01-HelloOs$ make qemu
+Press Ctrl-A and then X to exit QEMU
+qemu-system-riscv32 -nographic -smp 4 -machine virt -bios none -kernel os.elf
+Hello OS!
+QEMU: Terminated
+```

A1-Input/os.c

@@ -0,0 +1,46 @@
+#include <stdint.h>
+
+#define UART        0x10000000            // RISC-V 的 virt 虛擬機，其 UART 映射區起始位址為 0x10000000
+#define UART_THR    (uint8_t*)(UART+0x00) // THR:transmitter holding register 傳送暫存器
+#define UART_RHR    (uint8_t*)(UART+0x00) // THR:transmitter holding register 傳送暫存器
+#define UART_LSR    (uint8_t*)(UART+0x05) // LSR:line status register 輸出狀態暫存器
+#define UART_LSR_RX_READY 0x01            // input is waiting to be read from RHR
+#define UART_LSR_EMPTY_MASK 0x40          // LSR Bit 6: 當 LSR 的第六位元為 1 時，代表傳送區為空的，可以傳了 (Transmitter empty; both the THR and LSR are empty)
+
+void lib_putc(char ch) { // 透過 UART 傳送字元 ch 給宿主機印出
+	while ((*UART_LSR & UART_LSR_EMPTY_MASK) == 0); // 一直等到 UART LSR 傳送區為空，可以傳送了 
+	*UART_THR = ch; // 將字元 ch 發送出去
+}
+
+void lib_puts(char *s) { // 印出字串到宿主機。
+	while (*s) lib_putc(*s++);
+}
+
+char lib_getc() {
+	while ((*UART_LSR & UART_LSR_RX_READY) == 0); // 一直等到 UART RX_READY 有收到資料 
+	return *UART_RHR; // 傳回收到的字元
+}
+
+int lib_gets(char *s) {
+	char *p = s;
+	while (1) {
+		char ch = lib_getc();
+		lib_putc(ch);
+		if (ch == '\n' || ch == '\r') break;
+		*p++ = ch;
+	}
+	*p = '\0';
+	return p-s;
+}
+
+int os_main(void)
+{
+	lib_puts("type something:");
+	char str[100];
+	lib_gets(str);
+	lib_puts("\r\nyou type:");
+	lib_puts(str);
+	lib_puts("\r\n");
+	while (1) {} // 讓主程式卡在這裡，用無窮迴圈停止！
+	return 0;
+}

A1-Input/os.ld

@@ -0,0 +1,46 @@
+OUTPUT_ARCH( "riscv" ) /* 處理器架構為 RISCV */
+
+ENTRY( _start ) /* 進入點從 _start 開始執行 */
+
+MEMORY
+{
+  ram   (wxa!ri) : ORIGIN = 0x80000000, LENGTH = 128M /* RAM 從 0x80000000 開始，共 128M BYTES */
+}
+
+PHDRS
+{
+  text PT_LOAD; /* text 段要載入*/ /* PT_LOAD (1) Indicates that this program header describes a segment to be loaded from the file. 參考 -- https://ftp.gnu.org/old-gnu/Manuals/ld-2.9.1/html_node/ld_23.html */
+  data PT_LOAD; /* data 段要載入*/
+  bss PT_LOAD;  /* bss 段要載入*/
+}
+
+SECTIONS
+{
+  .text : {
+    PROVIDE(_text_start = .); /* 設定 _text_start 為 .text 段開頭位址。 */
+    *(.text.init) *(.text .text.*) /* 將所有程式碼放在這段。 */
+    PROVIDE(_text_end = .); /* 設定 _text_end 為 .text 段開頭位址。 */
+  } >ram AT>ram :text
+
+  .rodata : { /* 唯讀資料段 */
+    PROVIDE(_rodata_start = .);
+    *(.rodata .rodata.*)
+    PROVIDE(_rodata_end = .);
+  } >ram AT>ram :text
+
+  .data : { /* 資料段 */
+    . = ALIGN(4096);
+    PROVIDE(_data_start = .);
+    *(.sdata .sdata.*) *(.data .data.*)
+    PROVIDE(_data_end = .);
+  } >ram AT>ram :data
+
+  .bss :{ /* 未初始化資料段 */
+    PROVIDE(_bss_start = .);
+    *(.sbss .sbss.*) *(.bss .bss.*)
+    PROVIDE(_bss_end = .);
+  } >ram AT>ram :bss
+
+  PROVIDE(_memory_start = ORIGIN(ram));
+  PROVIDE(_memory_end = ORIGIN(ram) + LENGTH(ram));
+}

A1-Input/run.md

@@ -0,0 +1,16 @@
+# A1-Input
+
+## Build & Run
+
+```sh
+$ make clean
+rm -f *.elf
+$ make
+riscv64-unknown-elf-gcc -nostdlib -fno-builtin -mcmodel=medany -march=rv32ima -mabi=ilp32 -T os.ld -o os.elf start.s os.c
+$ make qemu
+Press Ctrl-A and then X to exit QEMU
+qemu-system-riscv32 -nographic -smp 4 -machine virt -bios none -kernel os.elf
+type something:hello
+you type:hello
+QEMU: Terminated
+```

A1-Input/start.s

@@ -0,0 +1,27 @@
+# 來源 -- https://matrix89.github.io/writes/writes/experiments-in-riscv/
+.equ STACK_SIZE, 8192
+
+.global _start
+
+_start:
+    # setup stacks per hart // hart: hardware thread, 差不多就是 core, 設定此 core 的堆疊
+    csrr t0, mhartid                # read current hart id // 讀取 core 的 id
+    slli t0, t0, 10                 # shift left the hart id by 1024 // t0 = t0*1024
+    la   sp, stacks + STACK_SIZE    # set the initial stack pointer // 將堆疊指標 sp 放到堆疊底端
+                                    # to the end of the stack space
+    add  sp, sp, t0                 # move the current hart stack pointer // 設定 hart 的堆疊位置
+                                    # to its place in the stack space
+
+    # park harts with id != 0
+    csrr a0, mhartid                # read current hart id
+    bnez a0, park                   # if we're not on the hart 0 // 如果不是 hart 0 ，就進入無窮迴圈。
+                                    # we park the hart
+
+    j    os_main                    # hart 0 jump to c // 堆疊設好了，讓 hart 0 進入 C 語言主程式。
+
+park:                               # 無窮迴圈，停住!
+    wfi
+    j park
+
+stacks:
+    .skip STACK_SIZE * 4            # allocate space for the harts stacks // 分配堆疊空間