diff --git a/baremetal/lib/syscalls.c b/baremetal/lib/syscalls.c
index a05be15..fd2d50a 100644
--- a/baremetal/lib/syscalls.c
+++ b/baremetal/lib/syscalls.c
@@ -64,13 +64,13 @@ int _write(int file, char *ptr, int len) {
 void _exit(int status) {
 #if defined(GEM5)
 #if defined(__arm__)
-    __asm__ __volatile__ ("mov r0, #0; mov r1, #0; .inst 0xEE000110 | (0x21 << 16);");
+    __asm__ __volatile__ ("mov r0, #0; mov r1, #0; .inst 0xEE000110 | (0x21 << 16);" : : : "r0", "r1");
 #elif defined(__aarch64__)
-    __asm__ __volatile__ ("mov x0, #0; .inst 0XFF000110 | (0x21 << 16);");
+    __asm__ __volatile__ ("mov x0, #0; .inst 0XFF000110 | (0x21 << 16);" : : : "x0");
 #endif
 #else
 #if defined(__arm__)
-    __asm__ __volatile__ ("mov r0, #0x18; ldr r1, =#0x20026; svc 0x00123456");
+    __asm__ __volatile__ ("mov r0, #0x18; ldr r1, =#0x20026; svc 0x00123456" : : : "r0", "r1");
 #elif defined(__aarch64__)
     /* TODO actually use the exit value here, just for fun. */
     __asm__ __volatile__ (
@@ -82,6 +82,9 @@ void _exit(int status) {
         "mov x1, sp\n" \
         "mov w0, #0x18\n" \
         "hlt 0xf000\n"
+        :
+        :
+        : "x0", "x1"
     );
 #endif
 #endif
diff --git a/include/ring0.h b/include/ring0.h
index b07a9b9..8c3a885 100644
--- a/include/ring0.h
+++ b/include/ring0.h
@@ -27,30 +27,46 @@ void ring0_get_control_regs(Ring0Regs *ring0_regs)
 #if defined(__x86_64__)
     __asm__ __volatile__ (
         "mov %%cr0, %%rax;"
-        "mov %%eax, %0;"
-        "mov %%cr2, %%rax;"
-        "mov %%eax, %1;"
-        "mov %%cr3, %%rax;"
-        "mov %%eax, %2;"
-        : "=m" (ring0_regs->cr0),
-          "=m" (ring0_regs->cr2),
-          "=m" (ring0_regs->cr3)
+        "mov %%eax, %[cr0];"
+        : [cr0] "=m" (ring0_regs->cr0)
         :
-        : "%rax"
+        : "rax"
+    );
+    __asm__ __volatile__ (
+        "mov %%cr2, %%rax;"
+        "mov %%eax, %[cr2];"
+        : [cr2] "=m" (ring0_regs->cr2)
+        :
+        : "rax"
+    );
+    __asm__ __volatile__ (
+        "mov %%cr3, %%rax;"
+        "mov %%eax, %[cr3];"
+        : [cr3] "=m" (ring0_regs->cr3)
+        :
+        : "rax"
     );
 #elif defined(__i386__)
     __asm__ __volatile__ (
         "mov %%cr0, %%eax;"
-        "mov %%eax, %0;"
-        "mov %%cr2, %%eax;"
-        "mov %%eax, %1;"
-        "mov %%cr3, %%eax;"
-        "mov %%eax, %2;"
-        : "=m" (ring0_regs->cr0),
-          "=m" (ring0_regs->cr2),
-          "=m" (ring0_regs->cr3)
+        "mov %%eax, %[cr0];"
+        : [cr0] "=m" (ring0_regs->cr0)
         :
-        : "%eax"
+        : "eax"
+    );
+    __asm__ __volatile__ (
+        "mov %%cr2, %%eax;"
+        "mov %%eax, %[cr2];"
+        : [cr2] "=m" (ring0_regs->cr2)
+        :
+        : "eax"
+    );
+    __asm__ __volatile__ (
+        "mov %%cr3, %%eax;"
+        "mov %%eax, %[cr3];"
+        : [cr3] "=m" (ring0_regs->cr3)
+        :
+        : "eax"
     );
 #endif
 }
diff --git a/userland/arch/aarch64/asm_hello.c b/userland/arch/aarch64/asm_hello.c
index 3765aea..8ca733a 100644
--- a/userland/arch/aarch64/asm_hello.c
+++ b/userland/arch/aarch64/asm_hello.c
@@ -2,7 +2,12 @@
 #include <inttypes.h>
 
 int main(void) {
-    register uint32_t x0 __asm__ ("x0");
-    __asm__ ("mov x0, #1;" : : : "%x0");
-    assert(x0 == 1);
+    uint32_t myvar = 1;
+    __asm__ (
+        "add %[myvar], %[myvar], 1;"
+        : [myvar] "=r" (myvar)
+        :
+        :
+    );
+    assert(myvar == 2);
 }
diff --git a/userland/arch/x86_64/asm_hello.c b/userland/arch/x86_64/asm_hello.c
index 6002371..53dbfa8 100644
--- a/userland/arch/x86_64/asm_hello.c
+++ b/userland/arch/x86_64/asm_hello.c
@@ -5,11 +5,11 @@ int main(void) {
 	uint32_t in = 1;
 	uint32_t out = 0;
 	__asm__ (
-		"movl %1, %%eax;"
+		"mov %[in], %%eax;"
 		"inc %%eax;"
-		"movl %%eax, %0"
-		: "=m" (out)
-		: "m" (in)
+		"mov %%eax, %[out]"
+		: [out] "=g" (out)
+		: [in] "g" (in)
 		: "%eax"
 	);
 	assert(out == in + 1);
diff --git a/userland/m5ops.h b/userland/m5ops.h
index a49d99a..9d4679c 100644
--- a/userland/m5ops.h
+++ b/userland/m5ops.h
@@ -4,44 +4,44 @@
 #if defined(__arm__)
 static void m5_checkpoint(void)
 {
-	__asm__ __volatile__ ("mov r0, #0; mov r1, #0; mov r2, #0; mov r3, #0; .inst 0xEE000110 | (0x43 << 16);");
+	__asm__ __volatile__ ("mov r0, #0; mov r1, #0; mov r2, #0; mov r3, #0; .inst 0xEE000110 | (0x43 << 16);" : : : "r0", "r1", "r2", "r3");
 };
 static void m5_dumpstats(void)
 {
-	__asm__ __volatile__ ("mov r0, #0; mov r1, #0; mov r2, #0; mov r3, #0; .inst 0xEE000110 | (0x41 << 16);");
+	__asm__ __volatile__ ("mov r0, #0; mov r1, #0; mov r2, #0; mov r3, #0; .inst 0xEE000110 | (0x41 << 16);" : : : "r0", "r1", "r2", "r3");
 };
 static void m5_exit()
 {
-	__asm__ __volatile__ ("mov r0, #0; mov r1, #0; .inst 0xEE000110 | (0x21 << 16);");
+	__asm__ __volatile__ ("mov r0, #0; mov r1, #0; .inst 0xEE000110 | (0x21 << 16);" : : : "r0", "r1");
 };
 static void m5_fail_1(void)
 {
-	__asm__ __volatile__ ("mov r0, #0; mov r1, #0; mov r2, #1; mov r3, #0; .inst 0xEE000110 | (0x22 << 16);");
+	__asm__ __volatile__ ("mov r0, #0; mov r1, #0; mov r2, #1; mov r3, #0; .inst 0xEE000110 | (0x22 << 16);" : : : "r0", "r1", "r2", "r3");
 };
 static void m5_resetstats(void)
 {
-	__asm__ __volatile__ ("mov r0, #0; mov r1, #0; mov r2, #0; mov r3, #0; .inst 0xEE000110 | (0x40 << 16);");
+	__asm__ __volatile__ ("mov r0, #0; mov r1, #0; mov r2, #0; mov r3, #0; .inst 0xEE000110 | (0x40 << 16);" : : : "r0", "r1", "r2", "r3");
 };
 #elif defined(__aarch64__)
 static void m5_checkpoint(void)
 {
-	__asm__ __volatile__ ("mov x0, #0; mov x1, #0; .inst 0xFF000110 | (0x43 << 16);");
+	__asm__ __volatile__ ("mov x0, #0; mov x1, #0; .inst 0xFF000110 | (0x43 << 16);" : : : "x0", "x1");
 };
 static void m5_dumpstats(void)
 {
-	__asm__ __volatile__ ("mov x0, #0; mov x1, #0; .inst 0xFF000110 | (0x41 << 16);");
+	__asm__ __volatile__ ("mov x0, #0; mov x1, #0; .inst 0xFF000110 | (0x41 << 16);" : : : "x0", "x1");
 };
 static void m5_exit(void)
 {
-	__asm__ __volatile__ ("mov x0, #0; .inst 0XFF000110 | (0x21 << 16);");
+	__asm__ __volatile__ ("mov x0, #0; .inst 0XFF000110 | (0x21 << 16);" : : : "x0");
 };
 static void m5_fail_1(void)
 {
-	__asm__ __volatile__ ("mov x0, #0; mov x1, #1; .inst 0xFF000110 | (0x22 << 16);");
+	__asm__ __volatile__ ("mov x0, #0; mov x1, #1; .inst 0xFF000110 | (0x22 << 16);" : : : "x0", "x1");
 };
 static void m5_resetstats(void)
 {
-	__asm__ __volatile__ ("mov x0, #0; mov x1, #0; .inst 0XFF000110 | (0x40 << 16);");
+	__asm__ __volatile__ ("mov x0, #0; mov x1, #0; .inst 0XFF000110 | (0x40 << 16);" : : : "x0", "x1");
 };
 #else
 static void m5_checkpoint(void) {};