Initial implementation of the MIPS assembler

libr/anal/p/anal_mips.c

@@ -120,6 +120,7 @@ static int mips_op(RAnal *anal, RAnalOp *op, ut64 addr, const ut8 *b, int len) {
 	} else 
 	if ((optype & 0x3e) == 2) {
 #if 0
+		// J-TYPE
 		 |--[0]--|  |--[1]--|  |--[2]--|  |--[3]--|
 		 1111 1111  1111 1111  1111 1111  1111 1111
 		 \_op__/\______address____________________/

libr/asm/arch/mips/mipsasm.c

@@ -0,0 +1,132 @@
+/* radare - Copyright 2012 - pancake */
+
+#include <r_types.h>
+
+static const char * const regs[32] = {
+  "zero", "at",   "v0",   "v1",   "a0",   "a1",   "a2",   "a3",
+  "a4",   "a5",   "a6",   "a7",   "t0",   "t1",   "t2",   "t3",
+  "s0",   "s1",   "s2",   "s3",   "s4",   "s5",   "s6",   "s7",
+  "t8",   "t9",   "k0",   "k1",   "gp",   "sp",   "s8",   "ra",
+  NULL
+};
+
+static struct {
+	const char *name;
+	int type;
+	int args;
+	int n;
+} ops[] = {
+	{ "nop", 'N', 0, NULL },
+	{ "lui", 'I', 2, 15 },
+	{ "sw", 'I', 3, 43 },
+	{ "sh", 'I', 3, 41 },
+	{ "sb", 'I', 3, 40 },
+	{ "lw", 'I', 3, 35 },
+	{ "lh", 'I', 3, 33 },
+	{ "lb", 'I', 3, 32 },
+	{ "ori", 'I', 3, 13 },
+	{ "andi", 'I', 3, 12 },
+	{ "xori", 'I', 3, 14 },
+	{ "addi", 'I', 3, 8 },
+	{ "addiu", 'I', 3, 9 },
+	{ "bnez", 'I', 2, 5 },
+	{ "jalr", 'R', 1, 9 },
+	{ "jr", 'R', 1, 8 },
+	{ "jal", 'J', 1, 3 },
+	{ "j",   'J', 1, 2 },
+	{ NULL }
+};
+
+static int mips_r (ut8 *b, int op, int rs, int rt, int rd, int sa, int fun) {
+	if (rs == -1 || rt == -1) return -1;
+	b[3] = ((op<<2)&0xfc) | ((rs>>3)&3);
+	b[2] = (rs<<5) | (rt&0x1f);
+	b[1] = ((rd<<3)&0xff) | (sa>>2);
+	b[0] = (fun&0x3f) | ((sa&3)<<5);
+	return 4;
+}
+
+static int mips_i (ut8 *b, int op, int rs, int rt, int imm) {
+	if (rs == -1 || rt == -1) return -1;
+	b[3] = ((op<<2)&0xfc) | ((rs>>3)&3);
+	b[2] = (rs<<5) | (rt);
+	b[1] = (imm>>8) &0xff;
+	b[0] = imm & 0xff;
+	return 4;
+}
+
+static int mips_j (ut8 *b, int op, int addr) {
+	addr /= 4;
+	b[3] = ((op<<2)&0xfc) | ((addr>>24)&3);
+	b[2] = (addr>>16)&0xff;
+	b[1] = (addr>>8) &0xff;
+	b[0] = addr & 0xff;
+	return 4;
+}
+
+static int getreg (const char *p) {
+	int n = (int) r_num_get (NULL, p);
+	if (n==0) {
+		if (strcmp (p, "0")) {
+			for (n=0; regs[n]; n++) {
+				if (!strcmp (p, regs[n]))
+					return n;
+			}
+		} else n = -1;
+	}
+	return n;
+}
+
+int mips_assemble(const char *str, ut64 pc, ut8 *out) {
+	int i, hasp;
+	char *s = strdup (str);
+	char w0[32], w1[32], w2[32], w3[32];
+	r_str_replace_char (s, ',', ' ');
+	hasp = r_str_replace_char (s, '(', ' ');
+	r_str_replace_char (s, ')', ' ');
+	*out = 0;
+	*w0=*w1=*w2=*w3=0;
+	sscanf (s, "%31s", w0); 
+	if (*w0)
+	for (i=0; ops[i].name; i++) {
+		if (!strcmp (ops[i].name, w0)) {
+			switch (ops[i].args) {
+			case 1: sscanf (s, "%31s %31s", w0, w1); break;
+			case 2: sscanf (s, "%31s %31s %31s", w0, w1, w2); break;
+			case 3: sscanf (s, "%31s %31s %31s %31s", w0, w1, w2, w3); break;
+			}
+			if (hasp) {
+				char tmp[32];
+				strcpy (tmp, w2);
+				strcpy (w2, w3);
+				strcpy (w3, tmp);
+			}
+			switch (ops[i].type) {
+			case 'N': // nop
+				memset (out, 0, 4);
+				break;
+			case 'R':
+				switch (ops[i].args) {
+				case 1: return mips_r (out, 0, getreg (w1), getreg (w2), getreg (w3), 0, ops[i].n);
+				case 2: return mips_i (out, ops[i].n, 0, getreg (w1), getreg (w2)); break;
+				case 3: return mips_i (out, ops[i].n, getreg (w1), getreg (w2), getreg (w3)); break;
+				}
+				break;
+			case 'I':
+				switch (ops[i].args) {
+				case 2: return mips_i (out, ops[i].n, 0, getreg (w1), getreg (w2)); break;
+				case 3: return mips_i (out, ops[i].n, getreg (w2), getreg (w1), getreg (w3)); break;
+				}
+				break;
+			case 'J':
+				switch (ops[i].args) {
+				case 1: return mips_j (out, ops[i].n, getreg (w1)); break;
+				}
+				break;
+			}
+			return -1;
+		}
+	}
+	free (s);
+	return -1;
+}

libr/include/r_util.h

@@ -356,7 +356,7 @@ R_API char* r_str_replace(char *str, const char *key, const char *val, int g);
 R_API void r_str_cpy(char *dst, const char *src);
 R_API int r_str_bits (char *strout, const ut8 *buf, int len, const char *bitz);
 R_API int r_str_rwx(const char *str);
-R_API void r_str_replace_char (char *s, int a, int b);
+R_API int r_str_replace_char (char *s, int a, int b);
 R_API const char *r_str_rwx_i(int rwx);
 R_API void r_str_writef(int fd, const char *fmt, ...);
 R_API char **r_str_argv(const char *str, int *_argc);

libr/util/str.c

@@ -69,12 +69,14 @@ main () {
 }
 #endif
 
-R_API void r_str_replace_char (char *s, int a, int b) {
+R_API int r_str_replace_char (char *s, int a, int b) {
+	int ret = 0;
 	char *o = s;
 	for (; *o; s++, o++) {
 		if (*o==a) {
 			if (b) {
 				*s = b;
+				ret++;
 				continue;
 			}
 			o++;
@@ -82,6 +84,7 @@ R_API void r_str_replace_char (char *s, int a, int b) {
 		*s = *o;
 	}
 	*s = 0;
+	return ret;
 }
 
 // TODO: do not use toupper.. must support modes to also append lowercase chars like in r1