arm: add dcc "uart" functionality
diff --git a/arch/arm/dcc.S b/arch/arm/dcc.S
new file mode 100644
index 0000000..8e4b48c
--- /dev/null
+++ b/arch/arm/dcc.S
@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2008 Brian Swetland
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files
+ * (the "Software"), to deal in the Software without restriction,
+ * including without limitation the rights to use, copy, modify, merge,
+ * publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+.global dcc_putc
+.global dcc_getc
+
+#if defined(ARM_CPU_ARM1136)
+dcc_getc:
+ mrc 14, 0, r0, c0, c1, 0
+ tst r0, #(1 << 30)
+ moveq r0, #-1
+ mrcne 14, 0, r0, c0, c5, 0
+ bx lr
+
+dcc_putc:
+ mrc 14, 0, r15, c0, c1, 0
+ mcrcc 14, 0, r0, c0, c5, 0
+ movcc r0, #0
+ movcs r0, #-1
+ bx lr
+#endif
\ No newline at end of file
diff --git a/arch/arm/include/arch/arm/dcc.h b/arch/arm/include/arch/arm/dcc.h
new file mode 100644
index 0000000..ba1aba0
--- /dev/null
+++ b/arch/arm/include/arch/arm/dcc.h
@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2008 Brian Swetland
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files
+ * (the "Software"), to deal in the Software without restriction,
+ * including without limitation the rights to use, copy, modify, merge,
+ * publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef __ARCH_ARM_DCC_H
+#define __ARCH_ARM_DCC_H
+
+/* returns < 0 if no data available */
+int dcc_getc(void);
+
+/* returns < 0 if output register was already full */
+int dcc_putc(unsigned c);
+
+#endif
diff --git a/arch/arm/rules.mk b/arch/arm/rules.mk
index f74da67..a08ad5c 100644
--- a/arch/arm/rules.mk
+++ b/arch/arm/rules.mk
@@ -95,7 +95,8 @@
$(LOCAL_DIR)/exceptions.o \
$(LOCAL_DIR)/faults.o \
$(LOCAL_DIR)/mmu.o \
- $(LOCAL_DIR)/thread.o
+ $(LOCAL_DIR)/thread.o \
+ $(LOCAL_DIR)/dcc.o
# set the default toolchain to arm elf and set a #define
TOOLCHAIN_PREFIX ?= arm-elf-