diff --git a/librz/asm/p/asm_sysz.c b/librz/asm/p/asm_sysz.c
index 0e7e3970d39..893eeb32936 100644
--- a/librz/asm/p/asm_sysz.c
+++ b/librz/asm/p/asm_sysz.c
@@ -35,16 +35,15 @@ static int sysz_disassemble(RzAsm *a, RzAsmOp *op, const ut8 *buf, int len) {
 	if (n > 0) {
 		if (insn->size > 0) {
 			op->size = insn->size;
-			char *buf_asm = rz_str_newf("%s%s%s",
+			rz_asm_op_setf_asm(op, "%s%s%s",
 				insn->mnemonic, insn->op_str[0] ? " " : "",
 				insn->op_str);
-			if (buf_asm) {
-				char *ptrstr = strstr(buf_asm, "ptr ");
+			char *str = rz_asm_op_get_asm(op);
+			if (str) {
+				char *ptrstr = strstr(str, "ptr ");
 				if (ptrstr) {
 					memmove(ptrstr, ptrstr + 4, strlen(ptrstr + 4) + 1);
 				}
-				rz_asm_op_set_asm(op, buf_asm);
-				free(buf_asm);
 			}
 		}
 		cs_free(insn, n);
diff --git a/librz/asm/p/asm_tms320.c b/librz/asm/p/asm_tms320.c
index 403fd70a60c..5ecbc8c63b5 100644
--- a/librz/asm/p/asm_tms320.c
+++ b/librz/asm/p/asm_tms320.c
@@ -62,12 +62,11 @@ static int tms320c64x_disassemble(RzAsm *a, RzAsmOp *op, const ut8 *buf, int len
 		goto fin;
 	}
 	op->size = insn->size;
-	char *buf_asm = rz_str_newf("%s%s%s", insn->mnemonic, insn->op_str[0] ? " " : "", insn->op_str);
-	if (buf_asm) {
-		rz_str_replace_char(buf_asm, '%', 0);
-		rz_str_case(buf_asm, false);
-		rz_asm_op_set_asm(op, buf_asm);
-		free(buf_asm);
+	rz_asm_op_setf_asm(op, "%s%s%s", insn->mnemonic, insn->op_str[0] ? " " : "", insn->op_str);
+	char *str = rz_asm_op_get_asm(op);
+	if (str) {
+		rz_str_replace_char(str, '%', 0);
+		rz_str_case(str, false);
 	}
 	cs_free(insn, n);
 fin:
diff --git a/librz/asm/p/asm_tms320c64x.c b/librz/asm/p/asm_tms320c64x.c
index 1c19ed04f17..dee428190a2 100644
--- a/librz/asm/p/asm_tms320c64x.c
+++ b/librz/asm/p/asm_tms320c64x.c
@@ -54,12 +54,11 @@ static int tms320c64x_disassemble(RzAsm *a, RzAsmOp *op, const ut8 *buf, int len
 		goto fin;
 	}
 	op->size = insn->size;
-	char *buf_asm = rz_str_newf("%s%s%s", insn->mnemonic, insn->op_str[0] ? " " : "", insn->op_str);
-	if (buf_asm) {
-		rz_str_replace_char(buf_asm, '%', 0);
-		rz_str_case(buf_asm, false);
-		rz_asm_op_set_asm(op, buf_asm);
-		free(buf_asm);
+	rz_asm_op_setf_asm(op, "%s%s%s", insn->mnemonic, insn->op_str[0] ? " " : "", insn->op_str);
+	char *str = rz_asm_op_get_asm(op);
+	if (str) {
+		rz_str_replace_char(str, '%', 0);
+		rz_str_case(str, false);
 	}
 	cs_free(insn, n);
 fin: