Minix1.5/commands/dis88/dishand.c
static char *sccsid =
"@(#) dishand.c, Ver. 2.1 created 00:00:00 87/09/01";
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* *
* Copyright (C) 1987 G. M. Harding, all rights reserved *
* *
* Permission to copy and redistribute is hereby granted, *
* provided full source code, with all copyright notices, *
* accompanies any redistribution. *
* *
* This file contains the source code for most of the spe- *
* cialized handler routines of the disassembler program. *
* (The file disfp.c contains handler routines specific to *
* the 8087 numeric co-processor.) Each handler routine *
* interprets the opcode byte (and subsequent data bytes, *
* if any) of a particular family of opcodes, and is re- *
* sponsible for generating appropriate output. All of the *
* code in this file is highly MACHINE-SPECIFIC, and would *
* have to be rewritten for a different CPU. The handler *
* routines are accessed only via pointers in the optab[] *
* array, however, so machine dependencies are confined to *
* this file, its sister file "disfp.c", and the data file *
* "distabs.c". *
* *
* All of the code in this file is based on the assumption *
* of sixteen-bit integers. *
* *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#include "dis.h" /* Disassembler declarations */
int segflg; /* Segment-override flag */
unsigned char objbuf[OBJMAX]; /* Buffer for object code */
int objptr; /* Index into objbuf[] */
unsigned long PC; /* Current program counter */
/* * * * * * MISCELLANEOUS SUPPORTING ROUTINES * * * * * */
void
objini(j) /* Object code init routine */
register int j;
{
if ((segflg == 1) || (segflg == 2))
segflg *= 3;
else
segflg = 0;
objptr = 0;
objbuf[objptr++] = (unsigned char)(j);
}
void
objout() /* Object-code output routine */
{
register int k;
if ( ! objflg )
return;
else
{
printf("\t|");
if (symptr >= 0)
printf(" %05.5lx:",(PC + 1L - (long)(objptr)));
for (k = 0; k < objptr; ++k)
printf(" %02.2x",objbuf[k]);
putchar('\n');
}
}
void
badseq(j,k) /* Invalid-sequence routine */
register int j, k;
{
printf("\t.byte\t0x%02.2x\t\t| invalid code sequence\n",j);
printf("\t.byte\t0x%02.2x\n",k);
}
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* *
* This routine is the first of several opcode-specific *
* handlers, each of which is dedicated to a particular *
* opcode family. A pointer to a handler routine is con- *
* tained in the second field of each optab[] entry. The *
* dfhand() routine is the default handler, invoked when *
* no other handler is appropriate (generally, when an in- *
* valid opcode is encountered). *
* *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
void
dfhand(j)
register int j; /* Pointer to optab[] entry */
{/* * * * * * * * * * START OF dfhand() * * * * * * * * * */
segflg = 0;
printf("\t.byte\t0x%02.2x",j);
if (optab[j].min || optab[j].max)
putchar('\n');
else
printf("\t\t| unimplemented opcode\n");
}/* * * * * * * * * * * END OF dfhand() * * * * * * * * * * */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* *
* This is the single-byte handler, invoked whenever a *
* one-byte opcode is encountered. *
* *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
void
sbhand(j)
register int j; /* Pointer to optab[] entry */
{/* * * * * * * * * * START OF sbhand() * * * * * * * * * */
objini(j);
if (j == 0x2e) /* seg cs */
segflg = 1;
if ((j == 0x26) /* seg es */
|| (j == 0x36) /* seg ss */
|| (j == 0x3e)) /* seg ds */
segflg = 2;
printf("%s\n",optab[j].text);
objout();
}/* * * * * * * * * * * END OF sbhand() * * * * * * * * * * */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* *
* This is the handler for most of the processor's regular *
* arithmetic operations. *
* *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
void
aohand(j)
register int j; /* Pointer to optab[] entry */
{/* * * * * * * * * * START OF aohand() * * * * * * * * * */
register int k;
int m, n;
char b[64];
objini(j);
switch (j & 7)
{
case 0 :
case 1 :
case 2 :
case 3 :
printf("%s\t",optab[j].text);
FETCH(k);
printf("%s\n",mtrans(j,k,TR_STD));
break;
case 4 :
FETCH(k);
printf("%s\tal,*0x%02.2x\n",optab[j].text,k);
break;
case 5 :
FETCH(m);
FETCH(n);
k = (n << 8) | m;
if (lookext((long)(k),(PC - 1),b))
printf("%s\tax,#%s\n",optab[j].text,b);
else
printf("%s\tax,#0x%04.4x\n",optab[j].text,k);
break;
default :
dfhand(j);
break;
}
objout();
}/* * * * * * * * * * * END OF aohand() * * * * * * * * * * */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* *
* This is the handler for opcodes which perform short *
* (eight-bit) relative jumps. *
* *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
void
sjhand(j)
register int j; /* Pointer to optab[] entry */
{/* * * * * * * * * * START OF sjhand() * * * * * * * * * */
register int k;
int m;
objini(j);
FETCH(m);
if (m & 0x80)
k = 0xff00;
else
k = 0;
k |= m;
printf("%s\t%s\t\t| loc %05.5lx\n",optab[j].text,
lookup((PC + k + 1L),N_TEXT,LOOK_REL,-1L),
(PC + k + 1L));
objout();
}/* * * * * * * * * * * END OF sjhand() * * * * * * * * * * */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* *
* This is the handler for a loosely-knit family of op- *
* codes which perform arithmetic and logical operations, *
* and which take immediate data. The routine's logic is *
* rather complex, so, in an effort to avoid additional *
* complexity, the search for external references in the *
* relocation table has been dispensed with. Eager hackers *
* can try their hand at coding such a search. *
* *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
void
imhand(j)
register int j; /* Pointer to optab[] entry */
{/* * * * * * * * * * START OF imhand() * * * * * * * * * */
unsigned long pc;
register int k;
int offset, oflag, immed, iflag, mod, opi, w, rm;
int m, n;
static char a[100], b[30];
objini(j);
FETCH(k);
pc = PC + 1;
offset = 0;
mod = (k & 0xc0) >> 6;
opi = (k & 0x38) >> 3;
w = j & 1;
rm = k & 7;
if ((j & 2)
&& ((opi == 1)
|| (opi == 4)
|| (opi == 6)))
{
badseq(j,k);
return;
}
strcpy(a,OPFAM[opi]);
if ( ! w )
strcat(a,"b");
if ((oflag = mod) > 2)
oflag = 0;
if ((mod == 0) && (rm == 6))
{
FETCH(m);
FETCH(n);
offset = (n << 8) | m;
}
else if (oflag)
if (oflag == 2)
{
FETCH(m);
FETCH(n);
offset = (n << 8) | m;
}
else
{
FETCH(m);
if (m & 0x80)
n = 0xff00;
else
n = 0;
offset = n | m;
}
switch (j & 3)
{
case 0 :
case 2 :
FETCH(immed);
iflag = 0;
break;
case 1 :
FETCH(m);
FETCH(n);
immed = (n << 8) | m;
iflag = 1;
break;
case 3 :
FETCH(immed);
if (immed & 0x80)
immed &= 0xff00;
iflag = 0;
break;
}
strcat(a,"\t");
switch (mod)
{
case 0 :
if (rm == 6)
strcat(a,
lookup((long)(offset),N_DATA,LOOK_ABS,pc));
else
{
sprintf(b,"(%s)",REGS0[rm]);
strcat(a,b);
}
break;
case 1 :
case 2 :
if (mod == 1)
strcat(a,"*");
else
strcat(a,"#");
sprintf(b,"%d(",offset);
strcat(a,b);
strcat(a,REGS1[rm]);
strcat(a,")");
break;
case 3 :
strcat(a,REGS[(w << 3) | rm]);
break;
}
strcat(a,",");
if (iflag)
strcat(a,"#");
else
strcat(a,"*");
sprintf(b,"%d",immed);
strcat(a,b);
printf("%s\n",a);
objout();
}/* * * * * * * * * * * END OF imhand() * * * * * * * * * * */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* *
* This is the handler for various "mov"-type opcodes *
* which use the mod, reg, and r/m fields of the second *
* code byte in a standard, straightforward way. *
* *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
void
mvhand(j)
int j; /* Pointer to optab[] entry */
{/* * * * * * * * * * START OF mvhand() * * * * * * * * * */
register int k, m = j;
objini(j);
FETCH(k);
if ((m == 0x84) || (m == 0x85) /* Kind of kludgey */
|| (m == 0xc4) || (m == 0xc5)
|| (m == 0x8d))
if (m & 0x40)
m |= 0x03;
else
m |= 0x02;
printf("%s\t%s\n",optab[j].text,mtrans(m,k,TR_STD));
objout();
}/* * * * * * * * * * * END OF mvhand() * * * * * * * * * * */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* *
* This is the handler for segment-register "mov" opcodes. *
* *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
void
mshand(j)
register int j; /* Pointer to optab[] entry */
{/* * * * * * * * * * START OF mshand() * * * * * * * * * */
register int k;
objini(j);
FETCH(k);
if (k & 0x20)
{
badseq(j,k);
return;
}
printf("%s\t%s\n",optab[j].text,mtrans(j,k,TR_SEG));
objout();
}/* * * * * * * * * * * END OF mshand() * * * * * * * * * * */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* *
* This is the handler for pops, other than single-byte *
* pops. (The 8088 allows popping into any register, or *
* directly into memory, accessed either immediately or *
* through a register and an index.) *
* *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
void
pohand(j)
register int j; /* Pointer to optab[] entry */
{/* * * * * * * * * * START OF pohand() * * * * * * * * * */
char *a;
register int k;
objini(j);
FETCH(k);
if (k & 0x38)
{
badseq(j,k);
return;
}
printf("%s\t",optab[j].text);
a = mtrans((j & 0xfd),k,TR_STD);
mtrunc(a);
printf("%s\n",a);
objout();
}/* * * * * * * * * * * END OF pohand() * * * * * * * * * * */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* *
* This is the handler routine for intersegment calls and *
* jumps. Its output is never symbolic, because the host *
* linker does not allow symbolic intersegment address *
* references except by means of symbolic constants, and *
* any such constants in the symbol table, even if they *
* are of the appropriate value, may be misleading. In *
* compiled code, intersegment references should not be *
* encountered, and even in assembled code, they should *
* occur infrequently. If and when they do occur, however, *
* they will be disassembled in absolute form. *
* *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
void
cihand(j)
int j; /* Pointer to optab[] entry */
{/* * * * * * * * * * START OF cihand() * * * * * * * * * */
register int m, n;
objini(j);
printf("%s\t",optab[j].text);
FETCH(m);
FETCH(n);
printf("#0x%04.4x,",((n << 8) | m));
FETCH(m);
FETCH(n);
printf("#0x%04.4x\n",((n << 8) | m));
objout();
}/* * * * * * * * * * * END OF cihand() * * * * * * * * * * */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* *
* This is the handler for "mov" opcodes with immediate *
* data. *
* *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
void
mihand(j)
register int j; /* Pointer to optab[] entry */
{/* * * * * * * * * * START OF mihand() * * * * * * * * * */
register int k;
int m, n;
char b[64];
objini(j);
printf("%s",optab[j].text);
if (j & 8)
{
FETCH(m);
FETCH(n);
k = ((n << 8) | m);
if (lookext((long)(k),(PC - 1),b))
printf("#%s\n",b);
else
printf("#%d\n",k);
}
else
{
FETCH(m);
printf("*%d\n",m);
}
objout();
}/* * * * * * * * * * * END OF mihand() * * * * * * * * * * */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* *
* This is the handler for a family of quick-move opcodes. *
* *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
void
mqhand(j)
int j; /* Pointer to optab[] entry */
{/* * * * * * * * * * START OF mqhand() * * * * * * * * * */
unsigned long pc;
register int m, n;
objini(j);
pc = PC + 1;
FETCH(m);
FETCH(n);
m = (n << 8) | m;
printf("%s\t",optab[j].text);
if (j & 2)
printf("%s,%s\n",
lookup((long)(m),N_DATA,LOOK_ABS,pc),
REGS[(j & 1) << 3]);
else
printf("%s,%s\n",
REGS[(j & 1) << 3],
lookup((long)(m),N_DATA,LOOK_ABS,pc));
objout();
}/* * * * * * * * * * * END OF mqhand() * * * * * * * * * * */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* *
* This is the handler for a family of quick-test opcodes. *
* *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
void
tqhand(j)
int j; /* Pointer to optab[] entry */
{/* * * * * * * * * * START OF tqhand() * * * * * * * * * */
register int m, n;
int k;
char b[64];
objini(j);
printf("%s\t%s,",optab[j].text,REGS[(j & 1) << 3]);
FETCH(m);
if (j & 1)
{
FETCH(n);
k = ((n << 8) | m);
if (lookext((long)(k),(PC - 1),b))
printf("#%s\n",b);
else
printf("#%d\n",k);
}
else
{
if (m & 80)
m |= 0xff00;
printf("*%d\n",m);
}
objout();
}/* * * * * * * * * * * END OF tqhand() * * * * * * * * * * */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* *
* This is the handler for multiple-byte "return" opcodes. *
* The 8088 allows returns to take an optional 16-bit ar- *
* gument, which reflects the amount to be added to SP *
* after the pop of the return address. The idea is to *
* facilitate the use of local parameters on the stack. *
* After some rumination, it was decided to disassemble *
* any such arguments as absolute quantities, rather than *
* rummaging through the symbol table for possible corre- *
* sponding constants. *
* *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
void
rehand(j)
int j; /* Pointer to optab[] entry */
{/* * * * * * * * * * START OF rehand() * * * * * * * * * */
register int m, n;
objini(j);
FETCH(m);
FETCH(n);
m = (n << 8) | m;
printf("%s\t#0x%04.4x\n",optab[j].text,m);
objout();
}/* * * * * * * * * * * END OF rehand() * * * * * * * * * * */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* *
* This is the handler for "mov" opcodes involving memory *
* and immediate data. *
* *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
void
mmhand(j)
register int j; /* Pointer to optab[] entry */
{/* * * * * * * * * * START OF mmhand() * * * * * * * * * */
char *a;
register int k;
char b[64];
objini(j);
FETCH(k);
if (k & 0x38)
{
badseq(j,k);
return;
}
printf("%s",optab[j].text);
if ( ! (j & 1) )
putchar('b');
a = mtrans((j & 0xfd),(k & 0xc7),TR_STD);
mtrunc(a);
printf("\t%s,",a);
if (j & 1)
{
FETCH(j);
FETCH(k);
k = (k << 8) | j;
if (lookext((long)(k),(PC - 1),b))
printf("#%s\n",b);
else
printf("#%d\n",k);
}
else
{
FETCH(k);
printf("*%d\n",k);
}
objout();
}/* * * * * * * * * * * END OF mmhand() * * * * * * * * * * */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* *
* This is the handler for the 8088 family of shift and *
* rotate instructions. *
* *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
void
srhand(j)
register int j; /* Pointer to optab[] entry */
{/* * * * * * * * * * START OF srhand() * * * * * * * * * */
char *a;
register int k;
objini(j);
FETCH(k);
if ((k & 0x38) == 0x30)
{
badseq(j,k);
return;
}
printf("%s",OPFAM[((k & 0x38) >> 3) + 16]);
if ( ! (j & 1) )
putchar('b');
a = mtrans((j & 0xfd),(k & 0xc7),TR_STD);
mtrunc(a);
printf("\t%s",a);
if (j & 2)
printf(",cl\n");
else
printf(",*1\n");
objout();
}/* * * * * * * * * * * END OF srhand() * * * * * * * * * * */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* *
* This is the handler for the ASCII-adjust opcodes. *
* *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
void
aahand(j)
register int j; /* Pointer to optab[] entry */
{/* * * * * * * * * * START OF aahand() * * * * * * * * * */
register int k;
objini(j);
FETCH(k);
if (k != 0x0a)
{
badseq(j,k);
return;
}
printf("%s\n",optab[j].text);
objout();
}/* * * * * * * * * * * END OF aahand() * * * * * * * * * * */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* *
* This is the handler for port I/O opcodes which specify *
* the port address as an immediate operand. *
* *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
void
iohand(j)
register int j; /* Pointer to optab[] entry */
{/* * * * * * * * * * START OF iohand() * * * * * * * * * */
register int k;
objini(j);
FETCH(k);
printf("%s\t0x%02.2x\n",optab[j].text,k);
objout();
}/* * * * * * * * * * * END OF iohand() * * * * * * * * * * */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* *
* This is the handler for opcodes which perform long *
* (sixteen-bit) relative jumps and calls. *
* *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
void
ljhand(j)
register int j; /* Pointer to optab[] entry */
{/* * * * * * * * * * START OF ljhand() * * * * * * * * * */
register int k;
int m, n;
objini(j);
FETCH(m);
FETCH(n);
k = (n << 8) | m;
printf("%s\t%s\t\t| loc %05.5lx\n",optab[j].text,
lookup((PC + k + 1L),N_TEXT,LOOK_LNG,(PC - 1L)),
(PC + k + 1L));
objout();
}/* * * * * * * * * * * END OF ljhand() * * * * * * * * * * */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* *
* This is the handler for a pair of oddball opcodes (0xf6 *
* and 0xf7) which perform miscellaneous arithmetic opera- *
* tions not dealt with elsewhere. *
* *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
void
mahand(j)
register int j; /* Pointer to optab[] entry */
{/* * * * * * * * * * START OF mahand() * * * * * * * * * */
char *a;
register int k;
char b[64];
objini(j);
FETCH(k);
a = mtrans((j & 0xfd),(k & 0xc7),TR_STD);
mtrunc(a);
switch (((k = objbuf[1]) & 0x38) >> 3)
{
case 0 :
printf("\ttest");
break;
case 1 :
badseq(j,k);
return;
case 2 :
printf("\tnot");
break;
case 3 :
printf("\tneg");
break;
case 4 :
printf("\tmul");
break;
case 5 :
printf("\timul");
break;
case 6 :
printf("\tdiv");
break;
case 7 :
printf("\tidiv");
break;
}
if ( ! (j & 1) )
putchar('b');
printf("\t%s",a);
if (k & 0x38)
putchar('\n');
else
if (j & 1)
{
FETCH(j);
FETCH(k);
k = (k << 8) | j;
if (lookext((long)(k),(PC - 1),b))
printf(",#%s\n",b);
else
printf(",#%d\n",k);
}
else
{
FETCH(k);
printf(",*%d\n",k);
}
objout();
}/* * * * * * * * * * * END OF mahand() * * * * * * * * * * */
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* *
* This is the handler for miscellaneous jump, call, push, *
* and increment/decrement opcodes (0xfe and 0xff) which *
* are not dealt with elsewhere. *
* *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
void
mjhand(j)
register int j; /* Pointer to optab[] entry */
{/* * * * * * * * * * START OF mjhand() * * * * * * * * * */
char *a;
register int k;
objini(j);
FETCH(k);
a = mtrans((j & 0xfd),(k & 0xc7),TR_STD);
mtrunc(a);
switch (((k = objbuf[1]) & 0x38) >> 3)
{
case 0 :
printf("\tinc");
if ( ! (j & 1) )
putchar('b');
putchar('\t');
break;
case 1 :
printf("\tdec");
if ( ! (j & 1) )
putchar('b');
putchar('\t');
break;
case 2 :
if (j & 1)
printf("\tcall\t@");
else
goto BAD;
break;
case 3 :
if (j & 1)
printf("\tcalli\t@");
else
goto BAD;
break;
case 4 :
if (j & 1)
printf("\tjmp\t@");
else
goto BAD;
break;
case 5 :
if (j & 1)
printf("\tjmpi\t@");
else
goto BAD;
break;
case 6 :
if (j & 1)
printf("\tpush\t");
else
goto BAD;
break;
case 7 :
BAD :
badseq(j,k);
return;
}
printf("%s\n",a);
objout();
}/* * * * * * * * * * * END OF mjhand() * * * * * * * * * * */