Lift MSP430 machine language to RzIL: first 3 instructions and 1 addr…

…essing mode

librz/arch/isa/msp430/msp430_il.c

@@ -0,0 +1,227 @@
+// SPDX-FileCopyrightText: 2024 Mostafa Mahmoud <[email protected]>
+// SPDX-License-Identifier: LGPL-3.0-only
+
+#include <msp430/msp430_il.h>
+
+// ``The 16-bit program counter (PC/R0) points to the next instruction to be executed.``
+//      -- userguide, p. 44
+#define PC_SIZE 16
+// ``The low byte of a word is always an even address. The high byte is at the next odd address.
+//   For example, if a data word is located at address xxx4h, then the low byte of that data word
+//   is located at address xxx4h, and the high byte of that word is located at address xxx5h.``
+//      -- userguide, p. 26
+#define IS_BIG_ENDIAN false
+// implied by the width of the PC and other registers (which are used as pointers in the relevant addressing modes)
+#define MEM_ADDR_SIZE 16U
+
+static const char *msp430_register_names[] = {
+	"pc",
+	"sp",
+	"sr",
+	"cg",
+	"r4",
+	"r5",
+	"r6",
+	"r7",
+	"r8",
+	"r9",
+	"r10",
+	"r11",
+	"r12",
+	"r13",
+	"r14",
+	"r15",
+	NULL
+};
+
+#include "rz_il/rz_il_opbuilder_begin.h"
+
+#define MSP430_GETR(r)    VARG(msp430_register_names[r])
+#define MSP430_SETR(r, v) SETG(msp430_register_names[r], v)
+
+typedef struct {
+	RzILOpBitVector *first;
+	RzILOpBitVector *second;
+} BVPair;
+
+RZ_OWN RzILOpEffect *rz_msp430_dummy() {
+	return NOP();
+}
+
+RZ_OWN RzILOpPure *get_destination(const Msp430Instruction *op) {
+	switch (op->dst_mode) {
+	case DST_REG: {
+		RzILOpBitVector *reg = MSP430_GETR(op->dst);
+		if (op->word_sized & WORD_SIZED_READ) {
+			return reg;
+		}
+		return CAST(8, IL_FALSE, reg);
+	}
+	default: NOT_IMPLEMENTED; // TODO : other addressing modes
+	}
+}
+
+RZ_OWN BVPair get_destination_destructured(const Msp430Instruction *op) {
+	switch (op->dst_mode) {
+	case DST_REG: {
+		RzILOpBitVector *reg = MSP430_GETR(op->dst);
+		BVPair res;
+		res.first = CAST(8, IL_FALSE, reg);
+		res.second = CAST(8, IL_FALSE, SHIFTR0(DUP(reg), U8(8)));
+		return res;
+	}
+	default: {
+		BVPair dummy = { .first = U8(0), .second = U8(0) };
+		return dummy; // TODO : other addressing modes
+	}
+	}
+}
+
+RZ_OWN RzILOpEffect *set_destination(const Msp430Instruction *op, RzILOpBitVector *old_value, RzILOpBitVector *new_value) {
+	switch (op->dst_mode) {
+	case DST_REG: {
+		if (op->word_sized & WORD_SIZED_WRITE) {
+			return MSP430_SETR(op->dst, new_value);
+		}
+		// the general idea is: First we zero the lower byte through ANDing with 0xFF00
+		//                      Then we assign the lower byte to the (byte-length) result through ORing with 0x00<result>
+		// the overall effect is that only the lower byte is assigned, which is what byte-sized operations do
+		return MSP430_SETR(op->dst, LOGOR(LOGAND(old_value, U16(0xFF00)), UNSIGNED(16, new_value)));
+	}
+	default: return NOP(); // TODO : other addressing modes
+	}
+}
+
+RZ_OWN RzILOpBitVector *update_sr_nz_flags(RzILOpBitVector *new_value, RzILOpBitVector *old_sr_value) {
+	// the general idea is that we zero out the N and Z bits in the old SR value
+	// (by ANDing with a mask of all 1s except in those positions)
+	// and then we OR that resulting value with the new bits in the relevant positions and all 0s everywhere else
+
+	// index of the N flag in the SR register: 2
+	RzILOpBool *n_flag_value = MSB(new_value);
+	RzILOpBitVector *n_or_mask = SHIFTL0(BOOL_TO_BV(n_flag_value, 16), U8(2));
+
+	// index of the Z flag in the SR register: 1
+	RzILOpBool *z_flag_value = IS_ZERO(DUP(new_value)); // must DUP new_value because it has been used before
+	RzILOpBitVector *z_or_mask = SHIFTL0(BOOL_TO_BV(z_flag_value, 16), U8(1));
+
+	RzILOpBitVector *and_mask = U16(~(1 << 2 | 1 << 1));
+	RzILOpBitVector *or_mask = LOGOR(n_or_mask, z_or_mask);
+
+	return LOGOR(LOGAND(old_sr_value, and_mask), or_mask);
+}
+
+RZ_OWN RzILOpBitVector *update_sr_v_flag_rcc(RzILOpBitVector *old_value, RzILOpBool *old_carry, RzILOpBitVector *old_sr_value) {
+	// the idea is the same as set_nz_flags_from_result(...): we AND with a mask that zeroes out the bit we care about
+	// then we OR with a mask that have the bit we care about in the same position that we zeroed
+	RzILOpBool *v_flag_value = AND(
+		INV(MSB(old_value)),
+		old_carry);
+
+	return LOGOR(
+		LOGAND(old_sr_value, U16(~(1 << 8))), /* zero out position 8, leave all else the same */
+		SHIFTL0(BOOL_TO_BV(v_flag_value, 16), U8(8)) /* OR with the new value for the bit */
+	);
+}
+
+RZ_OWN RzILOpBitVector *update_sr_c_flag(RzILOpBool *new_carry, RzILOpBitVector *old_sr_value) {
+	return LOGOR(
+		LOGAND(old_sr_value, U16(~1)), /* zero out the 0th position (i.e. the carry bit) */
+		BOOL_TO_BV(new_carry, 16) /* OR with the new carry */
+	);
+}
+
+RZ_OWN RzILOpEffect *rz_msp430_lift_rrc_instr(RzAnalysis *analysis, const Msp430Instruction *op) {
+	// rotation is just a shift with filling
+	return SEQ6(
+		/* 1- get the carry (to use later as the filling for the MSB of the operand) */
+		SETL("old_sr", MSP430_GETR(MSP430_SR)),
+		SETL("carry", LSB(VARL("old_sr"))),
+		/* 2- get the operand (whether register, memory location, ...) */
+		SETL("operand", get_destination(op)),
+		/* 3- Perform the actual Rotate Right through Carry operation. Do:
+				a- Shift the operand by 1 to the right and fill with carry */
+		SETL("result", SHIFTR(VARL("carry"), VARL("operand"), U8(1))),
+		/* ...      b- Set the operand to the value of the previous computation */
+		set_destination(op, VARL("operand"), VARL("result")),
+		/* ...      c- Finally set the flags: NZ as usual, v especially for RCC, and the carry flag from the discarded LSB */
+		MSP430_SETR(MSP430_SR, update_sr_c_flag(LSB(VARL("operand")), update_sr_v_flag_rcc(VARL("operand"), VARL("carry"), update_sr_nz_flags(VARL("result"), VARL("old_sr"))))));
+}
+
+RZ_OWN RzILOpEffect *rz_msp430_lift_sxt_instr(RzAnalysis *analysis, const Msp430Instruction *op) {
+	return set_destination(op, NULL, SIGNED(16, get_destination(op)));
+}
+
+RZ_OWN RzILOpEffect *rz_msp430_lift_swpb_instr(RzAnalysis *analysis, const Msp430Instruction *op) {
+	// 1- get lower byte and upper byte of the operand
+	BVPair low_high = get_destination_destructured(op);
+	RzILOpBitVector *low_byte = low_high.first;
+	RzILOpBitVector *high_byte = low_high.second;
+
+	// 2- append them in reverse order
+	RzILOpBitVector *result = APPEND(low_byte, high_byte);
+
+	// 3- set them (flags aren't affected)
+	return set_destination(op, NULL, result);
+}
+
+RzILOpEffect *rz_msp430_lift_todo(RzAnalysis *analysis, const Msp430Instruction *op) {
+	NOT_IMPLEMENTED;
+}
+
+#include "rz_il/rz_il_opbuilder_end.h"
+
+static const MSP430InstructionLifter one_op_lifters[] = {
+	[MSP430_RRC] = rz_msp430_lift_rrc_instr,
+	[MSP430_SWPB] = rz_msp430_lift_swpb_instr,
+	[MSP430_RRA] = rz_msp430_lift_todo, // TODO
+	[MSP430_SXT] = rz_msp430_lift_sxt_instr,
+	[MSP430_PUSH] = rz_msp430_lift_todo, // TODO
+	[MSP430_CALL] = rz_msp430_lift_todo, // TODO
+	[MSP430_RETI] = rz_msp430_lift_todo, // TODO
+	[MSP430_UNUSED] = rz_msp430_lift_todo // TODO
+};
+RZ_OWN RzILOpEffect *rz_msp430_lift_single_operand_instr(RZ_NONNULL RzAnalysis *analysis, const Msp430Instruction *op) {
+	return one_op_lifters[op->iopcode](analysis, op);
+}
+
+RZ_OWN RzILOpEffect *rz_msp430_lift_double_operand_instr(RZ_NONNULL RzAnalysis *analysis, const Msp430Instruction *op) {
+	return rz_msp430_lift_todo(analysis, op);
+}
+
+RZ_OWN RzILOpEffect *rz_msp430_lift_jump_instr(RZ_NONNULL RzAnalysis *analysis, const Msp430Instruction *op) {
+	return rz_msp430_lift_todo(analysis, op);
+}
+
+RZ_OWN RZ_IPI RzILOpEffect *rz_msp430_lift_instr(RZ_NONNULL RzAnalysis *analysis, RZ_NONNULL const Msp430Instruction *op) {
+	rz_return_val_if_fail(analysis && op, NULL);
+
+	switch (op->itype) {
+	case MSP430_ONEOP: {
+		return rz_msp430_lift_single_operand_instr(analysis, op);
+	}
+	case MSP430_TWOOP: {
+		return rz_msp430_lift_double_operand_instr(analysis, op);
+	}
+	case MSP430_JUMP: {
+		return rz_msp430_lift_jump_instr(analysis, op);
+	}
+
+	// should never happen, op can't be an invalid instruction
+	default:
+		rz_warn_if_reached();
+		return rz_msp430_dummy();
+	}
+}
+
+RZ_OWN RZ_IPI RzAnalysisILConfig *rz_msp430_il_config(RZ_NONNULL RzAnalysis *analysis) {
+	rz_return_val_if_fail(analysis, NULL);
+
+	RzAnalysisILConfig *ilconf = rz_analysis_il_config_new(PC_SIZE, IS_BIG_ENDIAN, MEM_ADDR_SIZE);
+
+	ilconf->reg_bindings = msp430_register_names;
+
+	return ilconf;
+}
+
+#include "msp430_instruction_parse.inc"

librz/arch/isa/msp430/msp430_il.h

@@ -0,0 +1,50 @@
+// SPDX-FileCopyrightText: 2024 Mostafa Mahmoud <[email protected]>
+// SPDX-License-Identifier: LGPL-3.0-only
+
+#ifndef MSP430_IL_H
+#define MSP430_IL_H
+
+#include <rz_analysis.h>
+#include <msp430/msp430_disas.h>
+
+#define WORD_SIZED_READ  1
+#define WORD_SIZED_WRITE 2
+
+typedef enum {
+	SRC_REG,
+	SRC_INDX,
+	SRC_SYM,
+	SRC_ABS,
+	SRC_IND_REG,
+	SRC_IND_AUTOINC,
+	SRC_IMM
+} Msp430SourceAddressingMode;
+
+typedef enum {
+	DST_REG,
+	DST_INDX,
+	DST_SYM,
+	DST_ABS
+} Msp430DestinationAddressingMode;
+
+typedef struct {
+	ut8 itype;
+	ut8 iopcode;
+	ut8 word_sized;
+
+	Msp430SourceAddressingMode src_mode;
+	ut32 src;
+
+	Msp430DestinationAddressingMode dst_mode;
+	ut32 dst;
+} Msp430Instruction;
+
+typedef RzILOpEffect *(*MSP430InstructionLifter)(RzAnalysis *analysis, const Msp430Instruction *op);
+
+RZ_OWN RZ_IPI RzILOpEffect *rz_msp430_lift_instr(RZ_NONNULL RzAnalysis *analysis, RZ_NONNULL const Msp430Instruction *op);
+
+RZ_OWN RZ_IPI RzAnalysisILConfig *rz_msp430_il_config(RZ_NONNULL RzAnalysis *analysis);
+
+void rz_msp430_instruction_from_command(RZ_OUT RZ_NONNULL Msp430Instruction *op, RZ_NONNULL struct msp430_cmd *cmd);
+
+#endif