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target-m68k: introduce read_imXX() functions
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Read a 8, 16 or 32bit immediat constant.

An immediate constant is stored in the instruction opcode and
can be in one or two extension words.

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Richard Henderson <rth@twiddle.net>
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@vivier
vivier committed Oct 25, 2016
1 parent d863362 commit 28b68cd
Showing 1 changed file with 41 additions and 50 deletions.
91 changes: 41 additions & 50 deletions target-m68k/translate.c
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Expand Up @@ -268,14 +268,27 @@ static TCGv gen_ldst(DisasContext *s, int opsize, TCGv addr, TCGv val,
}
}

/* Read a 16-bit immediate constant */
static inline uint16_t read_im16(CPUM68KState *env, DisasContext *s)
{
uint16_t im;
im = cpu_lduw_code(env, s->pc);
s->pc += 2;
return im;
}

/* Read an 8-bit immediate constant */
static inline uint8_t read_im8(CPUM68KState *env, DisasContext *s)
{
return read_im16(env, s);
}

/* Read a 32-bit immediate constant. */
static inline uint32_t read_im32(CPUM68KState *env, DisasContext *s)
{
uint32_t im;
im = ((uint32_t)cpu_lduw_code(env, s->pc)) << 16;
s->pc += 2;
im |= cpu_lduw_code(env, s->pc);
s->pc += 2;
im = read_im16(env, s) << 16;
im |= 0xffff & read_im16(env, s);
return im;
}

Expand Down Expand Up @@ -309,8 +322,7 @@ static TCGv gen_lea_indexed(CPUM68KState *env, DisasContext *s, TCGv base)
uint32_t bd, od;

offset = s->pc;
ext = cpu_lduw_code(env, s->pc);
s->pc += 2;
ext = read_im16(env, s);

if ((ext & 0x800) == 0 && !m68k_feature(s->env, M68K_FEATURE_WORD_INDEX))
return NULL_QREG;
Expand All @@ -328,8 +340,7 @@ static TCGv gen_lea_indexed(CPUM68KState *env, DisasContext *s, TCGv base)
if ((ext & 0x30) > 0x10) {
/* base displacement */
if ((ext & 0x30) == 0x20) {
bd = (int16_t)cpu_lduw_code(env, s->pc);
s->pc += 2;
bd = (int16_t)read_im16(env, s);
} else {
bd = read_im32(env, s);
}
Expand Down Expand Up @@ -377,8 +388,7 @@ static TCGv gen_lea_indexed(CPUM68KState *env, DisasContext *s, TCGv base)
if ((ext & 3) > 1) {
/* outer displacement */
if ((ext & 3) == 2) {
od = (int16_t)cpu_lduw_code(env, s->pc);
s->pc += 2;
od = (int16_t)read_im16(env, s);
} else {
od = read_im32(env, s);
}
Expand Down Expand Up @@ -530,8 +540,7 @@ static TCGv gen_lea(CPUM68KState *env, DisasContext *s, uint16_t insn,
case 5: /* Indirect displacement. */
reg = AREG(insn, 0);
tmp = tcg_temp_new();
ext = cpu_lduw_code(env, s->pc);
s->pc += 2;
ext = read_im16(env, s);
tcg_gen_addi_i32(tmp, reg, (int16_t)ext);
return tmp;
case 6: /* Indirect index + displacement. */
Expand All @@ -540,16 +549,14 @@ static TCGv gen_lea(CPUM68KState *env, DisasContext *s, uint16_t insn,
case 7: /* Other */
switch (insn & 7) {
case 0: /* Absolute short. */
offset = cpu_ldsw_code(env, s->pc);
s->pc += 2;
offset = (int16_t)read_im16(env, s);
return tcg_const_i32(offset);
case 1: /* Absolute long. */
offset = read_im32(env, s);
return tcg_const_i32(offset);
case 2: /* pc displacement */
offset = s->pc;
offset += cpu_ldsw_code(env, s->pc);
s->pc += 2;
offset += (int16_t)read_im16(env, s);
return tcg_const_i32(offset);
case 3: /* pc index+displacement. */
return gen_lea_indexed(env, s, NULL_QREG);
Expand Down Expand Up @@ -656,19 +663,17 @@ static TCGv gen_ea(CPUM68KState *env, DisasContext *s, uint16_t insn,
switch (opsize) {
case OS_BYTE:
if (what == EA_LOADS) {
offset = cpu_ldsb_code(env, s->pc + 1);
offset = (int8_t)read_im8(env, s);
} else {
offset = cpu_ldub_code(env, s->pc + 1);
offset = read_im8(env, s);
}
s->pc += 2;
break;
case OS_WORD:
if (what == EA_LOADS) {
offset = cpu_ldsw_code(env, s->pc);
offset = (int16_t)read_im16(env, s);
} else {
offset = cpu_lduw_code(env, s->pc);
offset = read_im16(env, s);
}
s->pc += 2;
break;
case OS_LONG:
offset = read_im32(env, s);
Expand Down Expand Up @@ -961,8 +966,7 @@ DISAS_INSN(divl)
TCGv reg;
uint16_t ext;

ext = cpu_lduw_code(env, s->pc);
s->pc += 2;
ext = read_im16(env, s);
if (ext & 0x87f8) {
gen_exception(s, s->pc - 4, EXCP_UNSUPPORTED);
return;
Expand Down Expand Up @@ -1113,8 +1117,7 @@ DISAS_INSN(movem)
TCGv tmp;
int is_load;

mask = cpu_lduw_code(env, s->pc);
s->pc += 2;
mask = read_im16(env, s);
tmp = gen_lea(env, s, insn, OS_LONG);
if (IS_NULL_QREG(tmp)) {
gen_addr_fault(s);
Expand Down Expand Up @@ -1157,8 +1160,7 @@ DISAS_INSN(bitop_im)
opsize = OS_LONG;
op = (insn >> 6) & 3;

bitnum = cpu_lduw_code(env, s->pc);
s->pc += 2;
bitnum = read_im16(env, s);
if (bitnum & 0xff00) {
disas_undef(env, s, insn);
return;
Expand Down Expand Up @@ -1411,8 +1413,7 @@ static void gen_set_sr(CPUM68KState *env, DisasContext *s, uint16_t insn,
else if ((insn & 0x3f) == 0x3c)
{
uint16_t val;
val = cpu_lduw_code(env, s->pc);
s->pc += 2;
val = read_im16(env, s);
gen_set_sr_im(s, val, ccr_only);
}
else
Expand Down Expand Up @@ -1535,8 +1536,7 @@ DISAS_INSN(mull)

/* The upper 32 bits of the product are discarded, so
muls.l and mulu.l are functionally equivalent. */
ext = cpu_lduw_code(env, s->pc);
s->pc += 2;
ext = read_im16(env, s);
if (ext & 0x87ff) {
gen_exception(s, s->pc - 4, EXCP_UNSUPPORTED);
return;
Expand Down Expand Up @@ -1677,8 +1677,7 @@ DISAS_INSN(branch)
op = (insn >> 8) & 0xf;
offset = (int8_t)insn;
if (offset == 0) {
offset = cpu_ldsw_code(env, s->pc);
s->pc += 2;
offset = (int16_t)read_im16(env, s);
} else if (offset == -1) {
offset = read_im32(env, s);
}
Expand Down Expand Up @@ -1962,14 +1961,12 @@ DISAS_INSN(strldsr)
uint32_t addr;

addr = s->pc - 2;
ext = cpu_lduw_code(env, s->pc);
s->pc += 2;
ext = read_im16(env, s);
if (ext != 0x46FC) {
gen_exception(s, addr, EXCP_UNSUPPORTED);
return;
}
ext = cpu_lduw_code(env, s->pc);
s->pc += 2;
ext = read_im16(env, s);
if (IS_USER(s) || (ext & SR_S) == 0) {
gen_exception(s, addr, EXCP_PRIVILEGE);
return;
Expand Down Expand Up @@ -2036,8 +2033,7 @@ DISAS_INSN(stop)
return;
}

ext = cpu_lduw_code(env, s->pc);
s->pc += 2;
ext = read_im16(env, s);

gen_set_sr_im(s, ext, 0);
tcg_gen_movi_i32(cpu_halted, 1);
Expand All @@ -2063,8 +2059,7 @@ DISAS_INSN(movec)
return;
}

ext = cpu_lduw_code(env, s->pc);
s->pc += 2;
ext = read_im16(env, s);

if (ext & 0x8000) {
reg = AREG(ext, 12);
Expand Down Expand Up @@ -2130,8 +2125,7 @@ DISAS_INSN(fpu)
int set_dest;
int opsize;

ext = cpu_lduw_code(env, s->pc);
s->pc += 2;
ext = read_im16(env, s);
opmode = ext & 0x7f;
switch ((ext >> 13) & 7) {
case 0: case 2:
Expand Down Expand Up @@ -2413,8 +2407,7 @@ DISAS_INSN(fbcc)
offset = cpu_ldsw_code(env, s->pc);
s->pc += 2;
if (insn & (1 << 6)) {
offset = (offset << 16) | cpu_lduw_code(env, s->pc);
s->pc += 2;
offset = (offset << 16) | read_im16(env, s);
}

l1 = gen_new_label();
Expand Down Expand Up @@ -2539,8 +2532,7 @@ DISAS_INSN(mac)
s->done_mac = 1;
}

ext = cpu_lduw_code(env, s->pc);
s->pc += 2;
ext = read_im16(env, s);

acc = ((insn >> 7) & 1) | ((ext >> 3) & 2);
dual = ((insn & 0x30) != 0 && (ext & 3) != 0);
Expand Down Expand Up @@ -3011,8 +3003,7 @@ static void disas_m68k_insn(CPUM68KState * env, DisasContext *s)
{
uint16_t insn;

insn = cpu_lduw_code(env, s->pc);
s->pc += 2;
insn = read_im16(env, s);

opcode_table[insn](env, s, insn);
}
Expand Down

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