lib: Add mlibc

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 90 insertions, 0 deletions

diff --git a/lib/mlibc/sysdeps/linux/x86/arch-syscall.cpp b/lib/mlibc/sysdeps/linux/x86/arch-syscall.cpp
new file mode 100644
index 0000000..35fc8aa
--- /dev/null
+++ b/lib/mlibc/sysdeps/linux/x86/arch-syscall.cpp
@@ -0,0 +1,90 @@
+#include <bits/syscall.h>
+#include <sys/syscall.h>
+
+using sc_word_t = __sc_word_t;
+
+// Note: ebx is used for PIC (it holds a reference to the GOT), so we can't clobber it with gcc apparently,
+// and also need to make sure to restore it after a syscall
+
+sc_word_t __do_syscall0(long sc) {
+	sc_word_t ret;
+	asm volatile("int $0x80" : "=a"(ret) : "a"(sc) : "memory");
+	return ret;
+}
+
+sc_word_t __do_syscall1(long sc, sc_word_t arg1) {
+	sc_word_t ret;
+	asm volatile("xchg %%ebx, %%edi;"
+		"int $0x80;"
+		"xchg %%edi, %%ebx;"
+		: "=a"(ret)
+		: "a"(sc), "D"(arg1)
+		: "memory");
+	return ret;
+}
+
+sc_word_t __do_syscall2(long sc, sc_word_t arg1, sc_word_t arg2) {
+	sc_word_t ret;
+	asm volatile("xchg %%ebx, %%edi;"
+		"int $0x80;"
+		"xchg %%edi, %%ebx;"
+		: "=a"(ret)
+		: "a"(sc), "D"(arg1), "c"(arg2)
+		: "memory");
+	return ret;
+}
+
+sc_word_t __do_syscall3(long sc, sc_word_t arg1, sc_word_t arg2, sc_word_t arg3) {
+	sc_word_t ret;
+	asm volatile("xchg %%ebx, %%edi;"
+		"int $0x80;"
+		"xchg %%edi, %%ebx;"
+		: "=a"(ret)
+		: "a"(sc), "D"(arg1), "c"(arg2), "d"(arg3)
+		: "memory");
+	return ret;
+}
+
+sc_word_t __do_syscall4(long sc, sc_word_t arg1, sc_word_t arg2, sc_word_t arg3, sc_word_t arg4) {
+	sc_word_t ret;
+	asm volatile("xchg %%ebx, %%edi;"
+		"int $0x80;"
+		"xchg %%edi, %%ebx;"
+		: "=a"(ret)
+		: "a"(sc), "D"(arg1), "c"(arg2), "d"(arg3), "S"(arg4)
+		: "memory");
+	return ret;
+}
+
+sc_word_t __do_syscall5(long sc, sc_word_t arg1, sc_word_t arg2, sc_word_t arg3, sc_word_t arg4,
+		sc_word_t arg5) {
+	sc_word_t ret;
+	asm volatile("pushl %2;"
+		"push %%ebx;"
+		"mov 4(%%esp), %%ebx;"
+		"int $0x80;"
+		"pop %%ebx;"
+		"add $4, %%esp;"
+		: "=a"(ret)
+		: "a"(sc), "g"(arg1), "c"(arg2), "d"(arg3), "S"(arg4), "D"(arg5)
+		: "memory");
+	return ret;
+}
+
+sc_word_t __do_syscall6(long sc, sc_word_t arg1, sc_word_t arg2, sc_word_t arg3, sc_word_t arg4,
+		sc_word_t arg5, sc_word_t arg6) {
+	sc_word_t ret;
+	sc_word_t a1a6[2] = { arg1, arg6 };
+	asm volatile ("pushl %1;"
+		"push %%ebx;"
+		"push %%ebp;"
+		"mov 8(%%esp),%%ebx;"
+		"mov 4(%%ebx),%%ebp;"
+		"mov (%%ebx),%%ebx;"
+		"int $0x80;"
+		"pop %%ebp;"
+		"pop %%ebx;"
+		"add $4,%%esp;"
+		: "=a"(ret) : "g"(&a1a6), "a"(sc), "c"(arg2), "d"(arg3), "S"(arg4), "D"(arg5) : "memory");
+	return ret;
+}