ARMとRISC-Vでも実行出来る様に

README.md

@@ -1,13 +1,28 @@
-此れはlibcなしの「こんにちは、世界」のデモです。\
+此れはlibcなしの「こんにちは、世界」のデモです。
-Linux、FreeBSD、OpenBSD、NetBSD、及びmacOSで実行出来ますが、IntelやAMD CPUが必須に成ります。
 
-This is a libc-less "hello, world" demo.\
+This is a libc-less "hello, world" demo.
-It runs on Linux, FreeBSD, OpenBSD, NetBSD, and macOS, but requires an Intel or AMD CPU.
 
+## 対応 | Support
+| OS      | CPU     | 対応 | テスト済み |
+|---------|---------|------|------------|
+| Linux   | x86-64  | 〇   | 〇         |
+| Linux   | AArch64 | 〇   | 〇         |
+| Linux   | RISC-V  | 〇   | 〇         |
+| FreeBSD | x86-64  | 〇   | 〇         |
+| OpenBSD | x86-64  | ✕    | ✕          |
+| NetBSD  | x86-64  | 〇   | ✕          |
+| macOS   | x86-64  | 〇   | ✕          |
+| macOS   | AArch64 | 〇   | ✕          |
+| Windows | x86-64  | ✕    | ✕          |
+| Windows | AArch64 | ✕    | ✕          |
+
+## 使い方 | How to use
+
+### x86-64
 ```sh
 $ cc -nostdlib -static -masm=intel -o main main.c
 $ ls -thal main
--rwxr-xr-x  1 suwako suwako  1.6K 12月 15 15:57 main
+-rwxr-xr-x  1 suwako suwako  1.5K 12月 15 15:57 main
 $ file main
 main: ELF 64-bit LSB executable, x86-64, version 1 (FreeBSD), statically linked, not stripped
 $ objdump -M intel -d main
@@ -29,4 +44,36 @@ Disassembly of section .text:
   201213: 0f 05                         syscall
   201215: 5d                            pop     rbp
   201216: c3                            ret
+$ ./main
+こんにちは、世界！
+```
+
+### AArch64、RISC-V
+```sh
+$ cc -nostdlib -static -o main main.c
+$ ls -thal main
+-rwxrwxr-x 1 suwako suwako 5.5K 12月 15 16:54 main
+$ file main
+main: ELF 64-bit LSB executable, UCB RISC-V, RVC, double-float ABI, version 1 (SYSV), statically linked, BuildID[sha1]=〇〇, not stripped
+$ objdump -d main
+
+main:     file format elf64-littleriscv
+
+
+Disassembly of section .text:
+
+000000000001017c <_start>:
+   1017c:       00001797                auipc   a5,0x1
+   10180:       e8478793                addi    a5,a5,-380 # 11000 <msg>
+   10184:       04000893                li      a7,64
+   10188:       4505                    li      a0,1
+   1018a:       85be                    mv      a1,a5
+   1018c:       4671                    li      a2,28
+   1018e:       00000073                ecall
+   10192:       05d00893                li      a7,93
+   10196:       4501                    li      a0,0
+   10198:       00000073                ecall
+   1019c:       0001                    nop
+$ ./main
+こんにちは、世界！
 ```

main.c

@@ -1,33 +1,79 @@
 #if defined(__linux__)
+  #if defined(__x86_64__)
     #define SYS_WRITE 1
     #define SYS_EXIT 60
+    #define SYSCALL_INST "syscall"
+  #elif defined(__aarch64__)
+    #define SYS_WRITE 64
+    #define SYS_EXIT 93
+    #define SYSCALL_INST "svc #0"
+  #elif defined(__riscv) && __riscv_xlen == 64
+    #define SYS_WRITE 64
+    #define SYS_EXIT 93
+    #define SYSCALL_INST "ecall"
+  #endif
 #elif defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__)
   #define SYS_WRITE 4
   #define SYS_EXIT 1
+  #define SYSCALL_INST "syscall"
 #elif defined(__APPLE__)
   #define SYS_WRITE 0x2000004
   #define SYS_EXIT 0x2000001
+  #if defined(__x86_64__)
+    #define SYSCALL_INST "syscall"
+  #elif defined(__aarch64__)
+    #define SYSCALL_INST "svc #0"
+  #endif
 #endif
 
 char msg[] = "こんにちは、世界！\n";
 
+__attribute((naked))
 void _start() {
   asm volatile(
+  #if defined(__x86_64__)
     ".intel_syntax noprefix\n"
     "mov eax, %[sys_write]\n"
     "mov edi, 1\n"
     "mov rsi, offset msg\n"
     "mov edx, %[len]\n"
-    "syscall\n"
+    SYSCALL_INST "\n"
 
     "mov eax, %[sys_exit]\n"
     "xor edi, edi\n"
-    "syscall\n"
+    SYSCALL_INST "\n"
+  #elif defined(__aarch64__)
+    "mov x8, %[sys_write]\n"
+    "mov x0, #1\n"
+    "mov x1, %[msg]\n"
+    "mov x2, %[len]\n"
+    SYSCALL_INST "\n"
 
-    ".att_syntax prefix\n"
+    "mov x8, %[sys_exit]\n"
+    "mov x0, #0\n"
+    SYSCALL_INST "\n"
+  #elif defined(__riscv) && __riscv_xlen == 64
+    "li a7, %[sys_write]\n"
+    "li a0, 1\n"
+    "mv a1, %[msg]\n"
+    "li a2, %[len]\n"
+    SYSCALL_INST "\n"
+
+    "li a7, %[sys_exit]\n"
+    "li a0, 0\n"
+    SYSCALL_INST "\n"
+  #endif
     :: [sys_write] "i" (SYS_WRITE),
        [sys_exit] "i" (SYS_EXIT),
-       [len] "i" (sizeof(msg) - 1)
+       [len] "i" (sizeof(msg) - 1),
-    : "rax", "rdi", "rsi", "rdx", "rcx", "r11"
+       [msg] "r" (msg)
+    : "memory",
+  #if defined(__x86_64__)
+      "rax", "rdi", "rsi", "rdx"  // x86-64
+  #elif defined(__aarch64__)
+      "x0", "x1", "x2", "x8"      // AArch64
+  #elif defined(__riscv) && __riscv_xlen == 64
+      "a0", "a1", "a2", "a7"      // RISC-V
+  #endif
   );
 }