1 files changed, 54 insertions, 0 deletions
diff --git a/lib/darwin/manual-syscall.h b/lib/darwin/manual-syscall.h
new file mode 100644
index 0000000..4d847ac
--- /dev/null
+++ b/lib/darwin/manual-syscall.h
@@ -0,0 +1,54 @@
+#pragma once
+
+#define REG(var, reg) register long _##var __asm__(#reg) = var
+#define OREG(var, reg) register long var __asm__(#reg)
+
+__attribute__((always_inline))
+#if defined(__x86_64__)
+static int manual_syscall(long s, long a, long b, long c, long d, long e) {
+    if (s < 0)
+        s = -s | 1 << 24;
+    else
+        s |= 2 << 24;
+    REG(s, rax); REG(a, rdi); REG(b, rsi); REG(c, rdx); REG(d, rcx);
+    OREG(out, rax);
+    __asm__ volatile("push %1; syscall; pop %1"
+                     : "=r"(out)
+                     : "r"(e), "r"(_s), "r"(_a), "r"(_b), "r"(_c), "r"(_d));
+    return out;
+}
+#elif defined(__i386__)
+static int manual_syscall(long s, long a, long b, long c, long d, long e) {
+    REG(s, eax);
+    OREG(out, eax);
+    __asm__ volatile("push %6; push %5; push %4; push %3; push %2; push $0;"
+                     "mov %%esp, %%ecx;"
+                     "call 1f; 1: pop %%edx; add $(2f-1b), %%edx;"
+                     "sysenter;"
+                     "2: add $(6 * 4), %%esp"
+                     : "=r"(out)
+                     : "r"(_s), "g"(a), "g"(b), "g"(c), "g"(d), "g"(e)
+                     : "edx", "ecx");
+    return out;
+}
+#elif defined(__arm__)
+static int manual_syscall(long s, long a, long b, long c, long d, long e) {
+    REG(s, r12); REG(a, r0); REG(b, r1); REG(c, r2); REG(d, r3);
+    OREG(out, r0);
+    __asm__ volatile("push {%1}; svc #0x80; pop {%1}"
+                     : "=r"(out)
+                     : "r"(e), "r"(_s), "r"(_a), "r"(_b), "r"(_c), "r"(_d));
+    return out;
+}
+#elif defined(__arm64__)
+static int manual_syscall(long s, long a, long b, long c, long d, long e) {
+    REG(s, x16); REG(a, x0); REG(b, x1); REG(c, x2); REG(d, x3);
+    OREG(out, x0);
+    __asm__ volatile("str %1, [sp, #-0x10]!\n svc #0x80\n ldr %1, [sp], #0x10"
+                     : "=r"(out)
+                     : "r"(e), "r"(_s), "r"(_a), "r"(_b), "r"(_c), "r"(_d));
+    return out;
+}
+#else
+#error ?
+#endif