bshell: re-organise build into three separate components

bshell: the front-end binary
bshell.runtime: contains the parser, compiler, and classes needed to run bshell scripts
bshell.core: contains the builtin commandlets and aliases

bshell.runtime/runtime/opcode.c

@@ -0,0 +1,26 @@
+#include <bshell/runtime/opcode.h>
+#include <fx/int.h>
+
+#define BSHELL_OPCODE_MAX 0xFF
+#define ARG_MAX           0xFFFFFF
+
+bshell_instruction bshell_instruction_encode(
+	enum bshell_opcode opcode,
+	uint32_t arg)
+{
+	if (opcode > BSHELL_OPCODE_MAX) {
+		return BSHELL_INSTRUCTION_INVALID;
+	}
+
+	return fx_u32_htob((opcode & BSHELL_OPCODE_MAX) | (arg & ARG_MAX) << 8);
+}
+
+void bshell_instruction_decode(
+	bshell_instruction instr,
+	enum bshell_opcode *out_opcode,
+	uint32_t *out_arg)
+{
+	instr = fx_u32_btoh(instr);
+	*out_opcode = (instr & BSHELL_OPCODE_MAX);
+	*out_arg = ((instr >> 8) & ARG_MAX);
+}