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ppsspp/ext/disarm.cpp
Henrik Rydgard f75d14d3b5 ARM FPU jit work
2013-02-10 15:53:56 +01:00

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/* disarm -- a simple disassembler for ARM instructions
* (c) 2000 Gareth McCaughan
*
* This file may be distributed and used freely provided:
* 1. You do not distribute any version that lacks this
* copyright notice (exactly as it appears here, extending
* from the start to the end of the C-language comment
* containing these words)); and,
* 2. If you distribute any modified version, its source
* contains a clear description of the ways in which
* it differs from the original version, and a clear
* indication that the changes are not mine.
* There is no restriction on your permission to use and
* distribute object code or executable code derived from
* this.
*
* The original version of this file (or perhaps a later
* version by the original author) may or may not be
* available at http://web.ukonline.co.uk/g.mccaughan/g/software.html .
*
* Share and enjoy! -- g
*/
/* (*This* comment is NOT part of the notice mentioned in the
* distribution conditions above.)
*
* The bulk of this code was ripped brutally from the middle
* of a much more interesting piece of software whose purpose
* is to disassemble object files in the format known as AOF;
* it's quite clever at spotting blocks of non-code embedded
* in code, identifying labels, and so on.
*
* This program, on the other hand, is very much simpler.
* It simply disassembles one instruction at a time. Some
* traces of the original purpose can be seen here and there.
* You might want to make this do a two-phase disassembly,
* adding labels etc the second time around. I've made this
* work by loading the whole file into memory first, partly
* because that makes a two-pass approach easier.
*
* One word of warning: I believe that the syntax this program
* uses for the MSR instruction is now obsolete.
*
* Usage:
* disarm <filename> <base-address>
* will disassemble every word in <filename>.
*
* <base-address> should be something understood by strtol.
* So you can get hex (which is probably what you want)
* by prefixing "0x".
*
* The -r option will byte-reverse each word before it's
* disassembled.
*
* The code is rather unmaintainable. I'm sorry.
*
* Changes since original release:
* ????-??-?? v0.00 Initial release.
* 2007-09-02 v0.11 Change %X to %lX in a format string.
* (Thanks to Vincent Zweije for reporting this.)
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef unsigned int word;
typedef unsigned int address;
typedef unsigned int addrdiff;
#define W(x) ((word*)(x))
#define declstruct(name) typedef struct name s##name, * p##name
#define defstruct(name) struct name
#define defequiv(new,old) typedef struct old s##new, * p##new
declstruct(DisOptions);
declstruct(Instruction);
typedef enum {
target_None, /* instruction doesn't refer to an address */
target_Data, /* instruction refers to address of data */
target_FloatS, /* instruction refers to address of single-float */
target_FloatD, /* instruction refers to address of double-float */
target_FloatE, /* blah blah extended-float */
target_FloatP, /* blah blah packed decimal float */
target_Code, /* instruction refers to address of code */
target_Unknown /* instruction refers to address of *something* */
} eTargetType;
defstruct(Instruction) {
char text[128]; /* the disassembled instruction */
int undefined; /* non-0 iff it's an undefined instr */
int badbits; /* non-0 iff something reserved has the wrong value */
int oddbits; /* non-0 iff something unspecified isn't 0 */
int is_SWI; /* non-0 iff it's a SWI */
word swinum; /* only set for SWIs */
address target; /* address instr refers to */
eTargetType target_type; /* and what we expect to be there */
int offset; /* offset from register in LDR or STR or similar */
char * addrstart; /* start of address part of instruction, or 0 */
};
#define disopt_SWInames 1 /* use names, not &nnnn */
#define disopt_CommaSpace 2 /* put spaces after commas */
#define disopt_FIXS 4 /* bogus FIX syntax for ObjAsm */
#define disopt_ReverseBytes 8 /* byte-reverse words first */
defstruct(DisOptions) {
word flags;
const char * * regnames; /* pointer to 16 |char *|s: register names */
};
static pInstruction instr_disassemble(word, address, pDisOptions);
#define INSTR_grok_v4
/* Preprocessor defs you can give to affect this stuff:
* INSTR_grok_v4 understand ARMv4 instructions (halfword & sign-ext LDR/STR)
* INSTR_new_msr be prepared to produce new MSR syntax if asked
* The first of these is supported; the second isn't.
*/
/* Some important single-bit fields. */
#define Sbit (1<<20) /* set condition codes (data processing) */
#define Lbit (1<<20) /* load, not store (data transfer) */
#define Wbit (1<<21) /* writeback (data transfer) */
#define Bbit (1<<22) /* single byte (data transfer, SWP) */
#define Ubit (1<<23) /* up, not down (data transfer) */
#define Pbit (1<<24) /* pre-, not post-, indexed (data transfer) */
#define Ibit (1<<25) /* non-immediate (data transfer) */
/* immediate (data processing) */
#define SPSRbit (1<<22) /* SPSR, not CPSR (MRS, MSR) */
/* Some important 4-bit fields. */
#define RD(x) ((x)<<12) /* destination register */
#define RN(x) ((x)<<16) /* operand/base register */
#define CP(x) ((x)<<8) /* coprocessor number */
#define RDbits RD(15)
#define RNbits RN(15)
#define CPbits CP(15)
#define RD_is(x) ((instr&RDbits)==RD(x))
#define RN_is(x) ((instr&RNbits)==RN(x))
#define CP_is(x) ((instr&CPbits)==CP(x))
/* A slightly efficient way of telling whether two bits are the same
* or not. It's assumed that a<b.
*/
#define BitsDiffer(a,b) ((instr^(instr>>(b-a)))&(1<<a))
/* op = append(op,ip) === op += sprintf(op,"%s",ip),
* except that it's faster.
*/
static char * append(char * op, const char *ip) {
char c;
while ((c=*ip++)!=0) *op++=c;
return op;
}
/* op = hex8(op,w) === op += sprintf(op,"&%08lX",w), but faster.
*/
static char * hex8(char * op, word w) {
int i;
*op++='&';
for (i=28; i>=0; i-=4) *op++ = "0123456789ABCDEF"[(w>>i)&15];
return op;
}
/* op = reg(op,'x',n) === op += sprintf(op,"x%lu",n&15).
*/
static char * reg(char * op, char c, word n) {
*op++=c;
n&=15;
if (n>=10) { *op++='1'; n+='0'-10; } else n+='0';
*op++=(char)n;
return op;
}
/* op = num(op,n) appends n in decimal or &n in hex
* depending on whether n<100. It's assumed that n>=0.
*/
static char * num(char * op, word w) {
if (w>=100) {
int i;
word t;
*op++='&';
for (i=28; (t=(w>>i)&15)==0; i-=4) ;
for (; i>=0; i-=4) *op++ = "0123456789ABCDEF"[(w>>i)&15];
}
else {
/* divide by 10. You can prove this works by exhaustive search. :-) */
word t = w-(w>>2); t=(t+(t>>4)) >> 3;
{ word u = w-10*t;
if (u==10) { u=0; ++t; }
if (t) *op++=(char)(t+'0');
*op++=(char)(u+'0');
}
}
return op;
}
/* instr_disassemble
* Disassemble a single instruction.
*
* args: instr a single ARM instruction
* addr the address it's presumed to have come from
* opts cosmetic preferences for our output
*
* reqs: opts must be filled in right. In particular, it must contain
* a list of register names.
*
* return: a pointer to a structure containing the disassembled instruction
* and some other information about it.
*
* This is basically a replacement for the SWI Debugger_Disassemble,
* but it has the following advantages:
*
* + it's 3-4 times as fast
* + it's better at identifying undefined instructions,
* and instructions not invariant under { disassemble; ObjAsm; }
* + it provides some other useful information as well
* + its output syntax is the same as ObjAsm's input syntax
* (where possible)
* + it doesn't disassemble FIX incorrectly unless you ask it to
* + it's more configurable in some respects
*
* It also has the following disadvantages:
*
* - it increases the size of ObjDism
* - it doesn't provide so many `helpful' usage comments etc
* - it's less configurable in some respects
* - it doesn't (yet) know about ARMv4 instructions
*
* This function proceeds in two phases. The first is very simple:
* it works out what sort of instruction it's looking at and sets up
* three strings:
* - |mnemonic| (the basic mnemonic: LDR or whatever)
* - |flagchars| (things to go after the cond code: B or whatever)
* - |format| (a string describing how to display the instruction)
* The second phase consists of interpreting |format|, character by
* character. Some characters (e.g., letters) just mean `append this
* character to the output string'; some mean more complicated things
* like `append the name of the register whose number is in bits 12..15'
* or, worse, `append a description of the <op2> field'.
*
* I'm afraid the magic characters in |format| are rather arbitrary.
* One criterion in choosing them was that they should form a contiguous
* subrange of the character set! Sorry.
*
* Things I still want to do:
*
* - more configurability?
* - make it much faster, if possible
* - make it much smaller, if possible
*
* Format characters:
*
* \01..\05 copro register number from nybble (\001 == nybble 0, sorry)
* $ SWI number
* % register set for LDM/STM (takes note of bit 22 for ^)
* & address for B/BL
* ' ! if bit 21 set, else nothing (mnemonic: half a !)
* ( #regs for SFM (bits 22,15 = fpn, assumed already tweaked)
* ) copro opcode in bits 20..23 (for CDP)
* * op2 (takes note of bottom 12 bits, and bit 25)
* + FP register or immediate value: bits 0..3
* , comma or comma-space
* - copro extra info in bits 5..7 preceded by , omitted if 0
* . address in ADR instruction
* / address for LDR/STR (takes note of bit 23 & reg in bits 16..19)
* 0..4 register number from nybble
* 5..9 FP register number from nybble
* : copro opcode in bits 21..23 (for MRC/MCR)
* ; copro number in bits 8..11
*
* ADDED BY HRYDGARD:
* ^ 16-bit immediate
*
* NB that / takes note of bit 22, too, and does its own ! when
* appropriate.
*
* On typical instructions this seems to take about 100us on my ARM6;
* that's about 3000 cycles, which seems grossly excessive. I'm not
* sure where all those cycles are being spent. Perhaps it's possible
* to make it much, much faster. Most of this time is spent on phase 2.
*/
extern pInstruction
instr_disassemble(word instr, address addr, pDisOptions opts) {
static char flagchars[4];
static sInstruction result;
const char * mnemonic = 0;
char * flagp = flagchars;
const char * format = 0;
word fpn;
eTargetType poss_tt = target_None;
#ifdef INSTR_grok_v4
int is_v4 = 0;
#endif
/* PHASE 0. Set up default values for |result|. */
if (opts->flags & disopt_ReverseBytes) {
instr = ((instr & 0xFF00FF00) >> 8) | ((instr & 0x00FF00FF) << 8);
instr = (instr >> 16) | (instr << 16);
}
fpn = ((instr>>15)&1) + ((instr>>21)&2);
result.undefined = 0;
result.badbits = 0;
result.oddbits = 0;
result.is_SWI = 0;
result.target_type = target_None;
result.offset = 0x80000000;
result.addrstart = 0;
/* PHASE 1. Decode and classify instruction. */
switch ((instr>>24)&15) {
case 0:
/* multiply or data processing, or LDRH etc */
if ((instr&(15<<4))!=(9<<4)) goto lMaybeLDRHetc;
/* multiply */
if (instr&(1<<23)) {
/* int multiply */
mnemonic = "UMULL\0UMLAL\0SMULL\0SMLAL" + 6*((instr>>21)&3);
format = "3,4,0,2";
}
else {
if (instr&(1<<22)) goto lUndefined; /* "class C" */
/* short multiply */
if (instr&(1<<21)) {
mnemonic = "MLA";
format = "4,0,2,3";
}
else {
mnemonic = "MUL";
format = "4,0,2";
}
}
if (instr&Sbit) *flagp++='S';
break;
case 1:
if ((instr & 0x0FFFFFF0) == ((18 << 20) | (0xFFF << 8) | (1 << 4))) {
mnemonic = "B";
format = "0";
break;
} else if ((instr & 0x0FFFFFF0) == 0x12FFF30) {
mnemonic = "BL";
format = "0";
break;
}
case 3:
/* SWP or MRS/MSR or data processing */
// hrydgard addition: MOVW/MOVT
if ((instr & 0x0FF00000) == 0x03000000) {
mnemonic = "MOVW";
format = "3,^";
break;
}
else if ((instr & 0x0FF00000) == 0x03400000) {
mnemonic = "MOVT";
format = "3,^";
break;
}
else if ((instr&0x02B00FF0)==0x00000090) {
/* SWP */
mnemonic = "SWP";
format = "3,0,[4]";
if (instr&Bbit) *flagp++='B';
break;
}
else if ((instr&0x02BF0FFF)==0x000F0000) {
/* MRS */
mnemonic = "MRS";
format = (instr&SPSRbit) ? "3,SPSR" : "3,CPSR";
break;
}
else if ((instr&0x02BFFFF0)==0x0029F000) {
/* MSR psr<P=0/1...>,Rs */
mnemonic = "MSR";
format = (instr&SPSRbit) ? "SPSR,0" : "CPSR,0";
break;
}
else if ((instr&0x00BFF000)==0x0028F000) {
/* MSR {C,S}PSR_flag,op2 */
mnemonic = "MSR";
format = (instr&SPSRbit) ? "SPSR_flg,*" : "CPSR_flg,*";
if (!(instr&Ibit) && (instr&(15<<4)))
#ifdef INSTR_grok_v4
goto lMaybeLDRHetc;
#else
goto lUndefined; /* shifted reg in MSR illegal */
#endif
break;
}
/* fall through here */
lMaybeLDRHetc:
#ifdef INSTR_grok_v4
if ((instr&(14<<24))==0
&& ((instr&(9<<4))==(9<<4))) {
/* Might well be LDRH or similar. */
if ((instr&(Wbit+Pbit))==Wbit) goto lUndefined; /* "class E", case 1 */
if ((instr&(Lbit+(1<<6)))==(1<<6)) goto lUndefined; /* STRSH etc */
mnemonic = "STR\0LDR" + ((instr&Lbit) >> 18);
if (instr&(1<<6)) *flagp++='S';
*flagp++ = (instr&(1<<5)) ? 'B' : 'H';
format = "3,/";
/* aargh: */
if (!(instr&(1<<22))) instr |= Ibit;
is_v4=1;
break;
}
#endif
case 2:
/* data processing */
{ word op21 = instr&(15<<21);
if ((op21==(2<<21) || (op21==(4<<21))) /* ADD or SUB */
&& ((instr&(RNbits+Ibit+Sbit))==RN(15)+Ibit) /* imm, no S */
/*&& ((instr&(30<<7))==0 || (instr&3))*/) { /* normal rot */
/* ADD ...,pc,#... or SUB ...,pc,#...: turn into ADR */
mnemonic = "ADR";
format = "3,.";
if ((instr&(30<<7))!=0 && !(instr&3)) result.oddbits=1;
break;
}
mnemonic = "AND\0EOR\0SUB\0RSB\0ADD\0ADC\0SBC\0RSC\0"
"TST\0TEQ\0CMP\0CMN\0ORR\0MOV\0BIC\0MVN" /* \0 */
+ (op21 >> 19);
/* Rd needed for all but TST,TEQ,CMP,CMN (8..11) */
/* Rn needed for all but MOV,MVN (13,15) */
if (op21 < ( 8<<21)) format = "3,4,*";
else if (op21 < (12<<21)) {
format = "4,*";
if (instr&RDbits) {
if ((instr&Sbit) && RD_is(15))
*flagp++='P';
else result.oddbits=1;
}
if (!(instr&Sbit)) goto lUndefined; /* CMP etc, no S bit */
}
else if (op21 & (1<<21)) {
format = "3,*";
if (instr&RNbits) result.oddbits=1;
}
else format = "3,4,*";
if (instr&Sbit && (op21<(8<<21) || op21>=(12<<21))) *flagp++='S';
}
break;
case 4:
case 5:
case 6:
case 7:
/* undefined or STR/LDR */
if ((instr&Ibit) && (instr&(1<<4))) goto lUndefined; /* "class A" */
mnemonic = "STR\0LDR" + ((instr&Lbit) >> 18);
format = "3,/";
if (instr&Bbit) *flagp++='B';
if ((instr&(Wbit+Pbit))==Wbit) *flagp++='T';
poss_tt = target_Data;
break;
case 8:
case 9:
/* STM/LDM */
mnemonic = "STM\0LDM" + ((instr&Lbit) >> 18);
if (RN_is(13)) {
/* r13, so treat as stack */
word x = (instr&(3<<23)) >> 22;
if (instr&Lbit) x^=6;
{ const char * foo = "EDEAFDFA"+x;
*flagp++ = *foo++;
*flagp++ = *foo;
}
}
else {
/* not r13, so don't treat as stack */
*flagp++ = (instr&Ubit) ? 'I' : 'D';
*flagp++ = (instr&Pbit) ? 'B' : 'A';
}
format = "4',%";
break;
case 10:
case 11:
/* B or BL */
mnemonic = "B\0BL"+((instr&(1<<24))>>23);
format = "&";
break;
case 12:
case 13:
/* STC or LDC */
if (CP_is(1)) {
/* copro 1: FPU. This is STF or LDF. */
mnemonic = "STF\0LDF" + ((instr&Lbit) >> 18);
format = "8,/";
*flagp++ = "SDEP"[fpn];
poss_tt = (eTargetType)(target_FloatS+fpn);
}
else if (CP_is(2)) {
/* copro 2: this is LFM or SFM. */
mnemonic = "SFM\0LFM" + ((instr&Lbit) >> 18);
if (!fpn) fpn=4;
if (RN_is(13) && BitsDiffer(23,24)) {
if ((instr&255)!=fpn) goto lNonStackLFM;
/* r13 and U!=P, so treat as stack */
if (BitsDiffer(20,24)) {
/* L != P, so FD */
*flagp++ = 'F'; *flagp++ = 'D';
}
else {
/* L == P, so EA */
*flagp++ = 'E'; *flagp++ = 'A';
}
format = "8,(,[4]'";
}
else {
lNonStackLFM:
/* not r13 or U=P or wrong offset, so don't treat as stack */
format = "8,(,/";
poss_tt = target_FloatE;
}
}
else {
/* some other copro number: STC or LDC. */
mnemonic = "STC\0LDC" + ((instr&Lbit) >> 18);
format = ";,\004,/";
if (instr&(1<<22)) *flagp++ = 'L';
poss_tt = target_Unknown;
}
break;
case 14:
/* CDP or MRC/MCR */
if (instr&(1<<4)) {
/* MRC/MCR. */
if (CP_is(1)) {
/* copro 1: FPU. */
if ((instr&Lbit) && RD_is(15)) {
/* MCR in FPU with Rd=r15: comparison (ugh) */
if (!(instr&(1<<23))) goto lUndefined; /* unused operation */
mnemonic = "CMF\0\0CNF\0\0CMFE\0CNFE" + (5*(instr&(3<<21)) >> 21);
format = "9,+";
if (instr&((1<<19)+(7<<5)))
result.badbits=1; /* size,rmode reseved */
}
else {
/* normal FPU MCR/MRC */
word op20 = instr&(15<<20);
if (op20>=6<<20) goto lUndefined;
mnemonic = "FLT\0FIX\0WFS\0RFS\0WFC\0RFC" + (op20>>18);
if (op20==0) {
/* FLT instruction */
format = "9,3";
{ char c = "SDE*"[((instr>>7)&1) + ((instr>>18)&2)];
if (c=='*') goto lUndefined; else *flagp++=c;
}
if (instr&15) result.oddbits=1; /* Fm and const flag unused */
}
else {
/* not FLT instruction */
if (instr&((1<<7)+(1<<19)))
result.badbits=1; /* size bits reserved */
if (op20==1<<20) {
/* FIX instruction */
format = "3,+";
if (opts->flags&disopt_FIXS)
*flagp++ = "SDEP"[((instr>>7)&1) + ((instr>>18)&2)];
*flagp++ = "\0PMZ"[(instr&(3<<5))>>5];
if (instr&(7<<15)) result.oddbits=1; /* Fn unused */
if (instr&(1<<3)) result.badbits=1; /* no immediate consts */
}
else {
/* neither FLT nor FIX */
format = "3";
if (instr&(3<<5)) result.badbits=1; /* rmode reserved */
if (instr&(15+(7<<15))) result.oddbits=1;/* iFm, Fn unused */
}
}
}
}
else {
/* some other copro number. Not FPU. */
/* NB that ObjAsm documentation gets MCR and MRC the wrong way round!
*/
mnemonic = "MCR\0MRC";
mnemonic += (instr&Lbit) >> 18;
format = ";,:,3,\005,\001-";
}
}
else {
/* CDP. */
if (CP_is(1)) {
/* copro 1: FPU. */
mnemonic = /* dyadics: */
"ADF\0MUF\0SUF\0RSF\0"
"DVF\0RDF\0POW\0RPW\0"
"RMF\0FML\0FDV\0FRD\0"
"POL\0***\0***\0***\0"
/* monadics: */
"MVF\0MNF\0ABS\0RND\0"
"SQT\0LOG\0LGN\0EXP\0"
"SIN\0COS\0TAN\0ASN\0"
"ACS\0ATN\0URD\0NRM\0"
+ ((instr&(15<<20)) >> 18) /* opcode -> bits 5432 */
+ ((instr&(1<<15)) >> 9); /* monadicP -> bit 6 */
format = (instr&(1<<15)) ? "8,+" : "8,9,+";
*flagp++ = "SDE*"[((instr>>7)&1) + ((instr>>18)&2)];
*flagp++ = "\0PMZ"[(instr&(3<<5))>>5];
/* NB that foregoing relies on this being the last flag! */
if (*mnemonic=='*' || *flagchars=='*') goto lUndefined;
}
else {
/* some other copro number. Not FPU. */
mnemonic = "CDP";
format = ";,),\004,\005,\001-";
}
}
break;
case 15:
/* SWI */
mnemonic = "SWI";
format = "$";
break;
/* Nasty hack: this is code that won't be reached in the normal
* course of events, and after the last case of the switch is a
* convenient place for it.
*/
lUndefined:
strcpy(result.text, "Undefined instruction");
result.undefined = 1;
return &result;
}
*flagp=0;
/* PHASE 2. Produce string. */
{ char * op = result.text;
/* 2a. Mnemonic. */
op = append(op,mnemonic);
/* 2b. Condition code. */
{ word cond = instr>>28;
if (cond!=14) {
const char * ip = "EQNECSCCMIPLVSVCHILSGELTGTLEALNV"+2*cond;
*op++ = *ip++;
*op++ = *ip;
}
}
/* 2c. Flags. */
{ const char * ip = flagchars;
while (*ip) *op++ = *ip++;
}
/* 2d. A tab character. */
*op++ = '\t';
/* 2e. Other stuff, determined by format string. */
{ const char * ip = format;
char c;
const char * * regnames = opts->regnames;
word oflags = opts->flags;
while ((c=*ip++) != 0) {
switch(c) {
case '^': // hrydgard addition
{
unsigned short imm16 = ((instr & 0x000F0000) >> 4) | (instr & 0x0FFF);
op += sprintf(op, "%04x", imm16);
}
break;
case '$':
result.is_SWI = 1;
result.swinum = instr&0x00FFFFFF;
result.addrstart = op;
op += sprintf(op, "&%X", result.swinum);
break;
case '%':
*op++='{';
{ word w = instr&0xFFFF;
int i=0;
while (w) {
int j;
while (!(w&(1ul<<i))) ++i;
for (j=i+1; w&(1ul<<j); ++j) ;
--j;
/* registers [i..j] */
op = append(op, regnames[i]);
if (j-i) {
*op++ = (j-i>1) ? '-' : ',';
op = append(op, regnames[j]);
}
i=j; w=(w>>(j+1))<<(j+1);
if (w) *op++=',';
}
}
*op++='}';
if (instr&(1<<22)) *op++='^';
break;
case '&':
{ address target = (addr+8 + ((((int)instr)<<8)>>6)) & 0x03FFFFFC;
result.addrstart = op;
op = hex8(op, target);
result.target_type = target_Code;
result.target = target;
}
break;
case '\'':
lPling:
if (instr&Wbit) *op++='!';
break;
case '(':
*op++ = (char)('0'+fpn);
break;
case ')':
{ word w = (instr>>20)&15;
if (w>=10) { *op++='1'; *op++=(char)('0'-10+w); }
else *op++=(char)(w+'0');
}
break;
case '*':
case '.':
if (instr&Ibit) {
/* immediate constant */
word imm8 = (instr&255);
word rot = (instr>>7)&30;
if (rot && !(imm8&3) && c=='*') {
/* Funny immediate const. Guaranteed not '.', btw */
*op++='#'; *op++='&';
*op++="0123456789ABCDEF"[imm8>>4];
*op++="0123456789ABCDEF"[imm8&15];
*op++=',';
op = num(op, rot);
}
else {
imm8 = (imm8>>rot) | (imm8<<(32-rot));
if (c=='*') {
*op++='#';
if (imm8>256 && ((imm8&(imm8-1))==0)) {
/* only one bit set, and that later than bit 8.
* Represent as 1<<... .
*/
op = append(op,"1<<");
{ int n=0;
while (!(imm8&15)) { n+=4; imm8=imm8>>4; }
/* Now imm8 is 1, 2, 4 or 8. */
n += (0x30002010 >> 4*(imm8-1))&15;
op = num(op, n);
}
}
else {
if (((int)imm8)<0 && ((int)imm8)>-100) {
*op++='-'; imm8=-(int)imm8;
}
op = num(op, imm8);
}
}
else {
address a = addr+8;
if (instr&(1<<22)) a-=imm8; else a+=imm8;
result.addrstart=op;
op = hex8(op, a);
result.target=a; result.target_type=target_Unknown;
}
}
}
else {
/* rotated register */
const char * rot = "LSL\0LSR\0ASR\0ROR" + ((instr&(3<<5)) >> 3);
op = append(op, regnames[instr&15]);
if (instr&(1<<4)) {
/* register rotation */
if (instr&(1<<7)) goto lUndefined;
*op++=','; if (oflags&disopt_CommaSpace) *op++=' ';
op = append(op,rot); *op++=' ';
op = append(op,regnames[(instr&(15<<8))>>8]);
}
else {
/* constant rotation */
word n = instr&(31<<7);
if (!n) {
if (!(instr&(3<<5))) break;
else if ((instr&(3<<5))==(3<<5)) {
op = append(op, ",RRX");
break;
}
else n=32<<7;
}
*op++ = ','; if (oflags&disopt_CommaSpace) *op++=' ';
op = num(append(append(op,rot)," #"),n>>7);
}
}
break;
case '+':
if (instr&(1<<3)) {
word w = instr&7;
*op++='#';
if (w<6) *op++=(char)('0'+w);
else op = append(op, w==6 ? "0.5" : "10");
}
else {
*op++='f';
*op++=(char)('0'+(instr&7));
}
break;
case ',':
*op++=',';
if (oflags&disopt_CommaSpace) *op++=' ';
break;
case '-':
{ word w = instr&(7<<5);
if (w) {
*op++=',';
if (oflags&disopt_CommaSpace) *op++=' ';
*op++ = (char)('0'+(w>>5));
}
}
break;
case '/':
result.addrstart = op;
*op++='[';
op = append(op, regnames[(instr&RNbits)>>16]);
if (!(instr&Pbit)) *op++=']';
*op++=','; if (oflags&disopt_CommaSpace) *op++=' ';
/* For following, NB that bit 25 is always 0 for LDC, SFM etc */
if (instr&Ibit) {
/* shifted offset */
if (!(instr&Ubit)) *op++='-';
/* We're going to transfer to '*', basically. The stupid
* thing is that the meaning of bit 25 is reversed there;
* I don't know why the designers of the ARM did that.
*/
instr ^= Ibit;
if (instr&(1<<4)) {
#ifdef INSTR_grok_v4
if (is_v4 && !(instr&(15<<8))) {
ip = (instr&Pbit) ? "0]" : "0";
break;
}
#else
goto lUndefined; /* LSL r3 forbidden */
#endif
}
/* Need a ] iff it was pre-indexed; and an optional ! iff
* it's pre-indexed *or* a copro instruction,
* except that FPU operations don't need the !. Bletch.
*/
if (instr&Pbit) ip="*]'";
else if (instr&(1<<27)) {
if (CP_is(1) || CP_is(2)) {
if (!(instr&Wbit)) goto lUndefined;
ip="*";
}
else ip="*'";
}
else ip="*";
}
else {
/* immediate offset */
word offset;
if (instr&(1<<27)) {
/* LDF or LFM or similar */
offset = (instr&255)<<2;
}
#ifdef INSTR_grok_v4
else if (is_v4) offset = (instr&15) + ((instr&(15<<8))>>4);
#endif
else {
/* LDR or STR */
offset = instr&0xFFF;
}
*op++='#';
if (!(instr&Ubit)) {
if (offset) *op++='-';
else result.oddbits=1;
result.offset = -(int)offset;
}
else result.offset = offset;
op = num(op, offset);
if (RN_is(15) && (instr&Pbit)) {
/* Immediate, pre-indexed and PC-relative. Set target. */
result.target_type = poss_tt;
result.target = (instr&Ubit) ? addr+8 + offset
: addr+8 - offset;
if (!(instr&Wbit)) {
/* no writeback, either. Use friendly form. */
op = hex8(result.addrstart, result.target);
break;
}
}
if (instr&Pbit) { *op++=']'; goto lPling; }
else if (instr&(1<<27)) {
if (CP_is(1) || CP_is(2)) {
if (!(instr&Wbit)) goto lUndefined;
}
else goto lPling;
}
}
break;
case '0': case '1': case '2': case '3': case '4':
op = append(op, regnames[(instr>>(4*(c-'0')))&15]);
break;
case '5': case '6': case '7': case '8': case '9':
*op++='f';
*op++=(char)('0' + ((instr>>(4*(c-'5')))&7));
break;
case ':':
*op++ = (char)('0' + ((instr>>21)&7));
break;
case ';':
op = reg(op, 'p', instr>>8);
break;
default:
if (c<=5)
op = reg(op, 'c', instr >> (4*(c-1)));
else *op++ = c;
}
}
*op=0;
}
}
/* DONE! */
return &result;
}
static const char * reg_names[16] = {
"r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
"r8", "r9", "r10", "r11", "ip", "sp", "lr", "pc"
};
static sDisOptions options = {
disopt_CommaSpace,
reg_names
};
const char *ArmRegName(int r) {
return reg_names[r];
}
void ArmDis(unsigned int addr, unsigned int w, char *output) {
pInstruction instr = instr_disassemble(w, addr, &options);
char temp[256];
sprintf(output, "%08x\t%s", w, instr->text);
if (instr->undefined || instr->badbits || instr->oddbits) {
if (instr->undefined) sprintf(output, " [undefined instr %08x]", w);
if (instr->badbits) sprintf(output, " [illegal bits %08x]", w);
// HUH? LDR and STR gets this a lot
// strcat(output, " ? (extra bits)");
if (instr->oddbits) sprintf(temp, " [unexpected bits %08x]", w), strcat(output, temp);
}
// zap tabs
while (*output) {
if (*output == '\t')
*output = ' ';
output++;
}
}
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