1 files changed, 85 insertions, 0 deletions
diff --git a/src/eie2ugs/mips_cpu.c b/src/eie2ugs/mips_cpu.c
new file mode 100644
index 0000000..7138bcd
--- /dev/null
+++ b/src/eie2ugs/mips_cpu.c
@@ -0,0 +1,85 @@
+#include "mips.h"
+
+#include <stdlib.h>
+
+struct mips_cpu_impl{
+
+	uint32_t pc;
+	uint32_t pcN;
+	uint32_t regs[32];
+
+	mips_mem_h mem;
+};
+
+mips_cpu_h mips_cpu_create(mips_mem_h mem)
+{
+	unsigned i;
+	mips_cpu_h res=(mips_cpu_h)malloc(sizeof(struct mips_cpu_impl));
+
+	res->mem=mem;
+
+	res->pc=0;
+	res->pcN=4;	// NOTE: why does this make sense?
+
+	for( i=0;i<32;i++){
+		res->regs[i]=0;
+	}
+
+	return res;
+}
+
+void mips_cpu_free(mips_cpu_h state)
+{
+	free(state);
+}
+
+mips_error mips_cpu_get_register(
+	mips_cpu_h state,	//!< Valid (non-empty) handle to a CPU
+	unsigned index,		//!< Index from 0 to 31
+	uint32_t *value		//!< Where to write the value to
+)
+{
+	if(state==0)
+		return mips_ErrorInvalidHandle;
+	if(index>=32)
+		return mips_ErrorInvalidArgument;
+	if(value==0)
+		return mips_ErrorInvalidArgument;
+
+	*value = state->regs[index];
+	return mips_Success;
+}
+
+/*! Modifies one of the 32 general purpose MIPS registers. */
+mips_error mips_cpu_set_register(
+	mips_cpu_h state,	//!< Valid (non-empty) handle to a CPU
+	unsigned index,		//!< Index from 0 to 31
+	uint32_t value		//!< New value to write into register file
+)
+{
+	if(state==0)
+		return mips_ErrorInvalidHandle;
+	if(index>=32)
+		return mips_ErrorInvalidArgument;
+
+	// TODO : What about register zero?
+	state->regs[index]=value;
+
+	return mips_Success;
+}
+
+mips_error mips_cpu_step(mips_cpu_h state)
+{
+	uint32_t pc=state->pc;
+
+	if(state==0)
+		return mips_ErrorInvalidHandle;
+
+	//TODO: Here is where the magic happens
+	// - Fetch the instruction from memory (mips_mem_read)
+	// - Decode the instruction (is it R, I, J)?
+	// - Execute the instruction (do maths, access memory, ...)
+	// - Writeback the results (update registers, advance pc)
+
+	return mips_ErrorNotImplemented;
+}