93 lines
2.5 KiB
C
93 lines
2.5 KiB
C
long print(const void *buf, long count) {
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#if defined(__x86_64__)
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asm volatile (
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"syscall"
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:
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: "a"(1), "D"(1), "S"(buf), "d"(count) // RDI, RSI, RDX are used in x86-64 for write args
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: "rcx", "r11", "memory"
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);
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#elif defined(__aarch64__)
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asm ( "mov x0, #1\n" // Move the exit status into register x0
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"mov x1, %0\n" // Syscall number for 'exit' is 93 in AArch64
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"mov x2, %1\n" // Syscall number for 'exit' is 93 in AArch64
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"mov x8, #64\n" // Syscall number for 'exit' is 93 in AArch64
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"svc #0\n" // Make the syscall
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: // No output operands
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: "r" (buf), "r"(count) // Input operand: status
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: "x0", "x8" // Clobbered registers
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);
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#elif defined(__mips__)
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asm ( "li $a0, 1\n"
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"move $a1, %0\n"
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"move $a2, %1\n"
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"li $v0, 4004\n"
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"syscall"
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:
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: "r"(buf), "r"(count)
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: "a0", "a1", "a2", "v0" //TODO: temp registers clobbered by syscall should probably also be listed but this fn returns right away so it should be fine?
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);
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#endif
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return 0;
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}
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void exit(int status) {
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#if defined(__x86_64__)
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asm volatile(
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"syscall"
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:
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: "a"(60), "D"(status)
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:
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);
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#elif defined(__aarch64__)
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asm ( "mov x0, %0\n" // Move the exit status into register x0
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"mov x8, #93\n" // Syscall number for 'exit' is 93 in AArch64
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"svc #0\n" // Make the syscall
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: // No output operands
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: "r" ((long)status) // Input operand: status
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: "x0", "x8" // Clobbered registers
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);
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#elif defined(__mips__)
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asm ( "move $a0, %0\n"
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"li $v0, 4001\n"
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"syscall"
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:
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: "r" (status)
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: "a0", "v0"
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);
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#endif
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for(;;);
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}
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int main() {
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//void _start() {
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char *msg = "Hello World!\n";
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print(msg, 13);
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return 69;
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}
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void __libc_start_main() {exit(main());}
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void _start() {
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__libc_start_main();
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}
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void __start() {
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_start();
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}
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/*
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#if defined(__x86_64__)
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printf("Compiled for x86_64 architecture\n");
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#elif defined(__i386__)
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printf("Compiled for x86 architecture\n");
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#elif defined(__arm__)
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printf("Compiled for ARM architecture\n");
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#elif defined(__aarch64__)
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printf("Compiled for ARM64 architecture\n");
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#elif defined(__mips__)
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printf("Compiled for ARM architecture\n");
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#else
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printf("Unknown architecture\n");
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#endif
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*/
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