diff --git a/src/kernel/core/arch/sh4/arch_atomic.c b/src/kernel/core/arch/sh4/arch_atomic.c
new file mode 100644
index 0000000000..2efee59044
--- /dev/null
+++ b/src/kernel/core/arch/sh4/arch_atomic.c
@@ -0,0 +1,148 @@
+/*
+** Copyright 2001, Travis Geiselbrecht. All rights reserved.
+** Distributed under the terms of the NewOS License.
+*/
+
+#include <SupportDefs.h>
+
+
+int32
+user_atomic_add(vint32 *uval, int32 incr)
+{
+	int32 val;
+	int32 ret;
+
+	if ((addr)uval >= KERNEL_BASE && (addr)uval <= KERNEL_TOP)
+		goto error;
+
+	if (user_memcpy(&val, (int32 *)uval, sizeof(val)) < 0) 
+		goto error;
+
+	// XXX broken on non SH4-systems, or when interrupts are enabled
+	// XXX x86 must use the assembly functions directly in userspace and not this ones
+	ret = val;
+	val += incr;
+
+	if (user_memcpy((int32 *)uval, &val, sizeof(val)) < 0)
+		goto error;
+
+	return ret;
+
+error:
+	// XXX kill the app
+	return -1;
+}
+
+
+int32
+user_atomic_and(vint32 *uval, int32 incr)
+{
+	int val;
+	int ret;
+
+	if ((addr)uval >= KERNEL_BASE && (addr)uval <= KERNEL_TOP)
+		goto error;
+
+	if (user_memcpy(&val, (int32 *)uval, sizeof(val)) < 0) 
+		goto error;
+
+	// XXX broken on non SH4-systems, or when interrupts are enabled
+	// XXX x86 must use the assembly functions directly in userspace and not this ones
+	ret = val;
+	val &= incr;
+
+	if (user_memcpy((int32 *)uval, &val, sizeof(val)) < 0)
+		goto error;
+
+	return ret;
+
+error:
+	// XXX kill the app
+	return -1;
+}
+
+
+int32
+user_atomic_or(vint32 *uval, int32 incr)
+{
+	int val;
+	int ret;
+
+	if ((addr)uval >= KERNEL_BASE && (addr)uval <= KERNEL_TOP)
+		goto error;
+
+	if (user_memcpy(&val, (int32 *)uval, sizeof(val)) < 0) 
+		goto error;
+
+	// XXX broken on non SH4-systems, or when interrupts are enabled
+	// XXX x86 must use the assembly functions directly in userspace and not this ones
+	ret = val;
+	val |= incr;
+
+	if (user_memcpy((int32 *)uval, &val, sizeof(val)) < 0)
+		goto error;
+
+	return ret;
+
+error:
+	// XXX kill the app
+	return -1;
+}
+
+
+int32
+user_atomic_set(vint32 *uval, int32 set_to)
+{
+	int val;
+	int ret;
+
+	if ((addr)uval >= KERNEL_BASE && (addr)uval <= KERNEL_TOP)
+		goto error;
+
+	if (user_memcpy(&val, (int32 *)uval, sizeof(val)) < 0) 
+		goto error;
+
+	// XXX broken on non SH4-systems, or when interrupts are enabled
+	// XXX x86 must use the assembly functions directly in userspace and not this ones
+	ret = val;
+	val = set_to;
+
+	if (user_memcpy((int32 *)uval, &val, sizeof(val)) < 0)
+		goto error;
+
+	return ret;
+
+error:
+	// XXX kill the app
+	return -1;
+}
+
+
+int32
+user_atomic_test_and_set(vint32 *uval, int32 set_to, int32 test_val)
+{
+	int val;
+	int ret;
+
+	if ((addr)uval >= KERNEL_BASE && (addr)uval <= KERNEL_TOP)
+		goto error;
+
+	if (user_memcpy(&val, (int32 *)uval, sizeof(val)) < 0) 
+		goto error;
+
+	// XXX broken on non SH4-systems, or when interrupts are enabled
+	// XXX x86 must use the assembly functions directly in userspace and not this ones
+	ret = val;
+	if (val == test_val) {
+		val = set_to;
+		if (user_memcpy((int32 *)uval, &val, sizeof(val)) < 0)
+			goto error;
+	}
+
+	return ret;
+
+error:
+	// XXX kill the app
+	return -1;
+}
+