Skip to content

i86.cpp: Need different EA execution times per CPU variant (808x/80186/80286) #14632

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
galibert merged 1 commit into from
Dec 3, 2025
+54 −31
Merged

i86.cpp: Need different EA execution times per CPU variant (808x/80186/80286) #14632

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
3 changes: 3 additions & 0 deletions src/devices/cpu/i86/i186.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -167,6 +167,9 @@ i80186_cpu_device::i80186_cpu_device(const machine_config &mconfig, device_type
, m_irmx_irq_ack(*this)
{
memcpy(m_timing, m_i80186_timing, sizeof(m_i80186_timing));
// The Effective Address calculation times are already included in the
// instruction timings for the 80186, so fill the table with zeros.
memset(m_ea_timing, 0, sizeof(m_i80186_ea_timing));
set_irq_acknowledge_callback(*this, FUNC(i80186_cpu_device::inta_callback));
}

Expand Down
1 change: 1 addition & 0 deletions src/devices/cpu/i86/i186.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -85,6 +85,7 @@ class i80186_cpu_device : public i8086_common_cpu_device
virtual void write_word(uint32_t addr, uint16_t data) override;

static const uint8_t m_i80186_timing[200];
static const uint8_t m_i80186_ea_timing[200];

private:
void update_interrupt_state();
Expand Down
24 changes: 22 additions & 2 deletions src/devices/cpu/i86/i286.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -114,9 +114,9 @@ const uint8_t i80286_cpu_device::m_i80286_timing[] =
5, 5, 5, 5, /* port reads */
3, 3, 3, 3, /* port writes */

2, 3, 3, /* move, 8-bit */
2, 5, 3, /* move, 8-bit */
2, 3, /* move, 8-bit immediate */
2, 3, 3, /* move, 16-bit */
2, 5, 3, /* move, 16-bit */
2, 3, /* move, 16-bit immediate */
5, 5, 3, 3, /* move, AL/AX memory */
2, 5, 2, 3, /* move, segment registers */
Expand Down Expand Up @@ -164,6 +164,25 @@ const uint8_t i80286_cpu_device::m_i80286_timing[] =
13, /* (80186) BOUND */
};

// Effective Address calculation takes one extra clock if offset calculation
// requires summing 3 elements.
const uint8_t i80286_cpu_device::m_i80286_ea_timing[] =
{
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
};

DEFINE_DEVICE_TYPE(I80286, i80286_cpu_device, "i80286", "Intel 80286")

i80286_cpu_device::i80286_cpu_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
Expand All @@ -175,6 +194,7 @@ i80286_cpu_device::i80286_cpu_device(const machine_config &mconfig, const char *
, m_out_shutdown_func(*this)
{
memcpy(m_timing, m_i80286_timing, sizeof(m_i80286_timing));
memcpy(m_ea_timing, m_i80286_ea_timing, sizeof(m_i80286_ea_timing));
m_amask = 0xffffff;
memset(m_sregs, 0x00, sizeof(m_sregs));
m_sregs[CS] = 0xf000;
Expand Down
1 change: 1 addition & 0 deletions src/devices/cpu/i86/i286.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -150,6 +150,7 @@ class i80286_cpu_device : public i8086_common_cpu_device
address_space_config m_opcodes_config;
address_space_config m_io_config;
static const uint8_t m_i80286_timing[200];
static const uint8_t m_i80286_ea_timing[200];

enum {
FAULT_DE = 0,
Expand Down
26 changes: 22 additions & 4 deletions src/devices/cpu/i86/i86.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -80,6 +80,23 @@ const uint8_t i8086_cpu_device::m_i8086_timing[] =
18, 9,17, /* MOVS 16-bit */
};

const uint8_t i8086_cpu_device::m_i8086_ea_timing[] =
{
7, 8, 8, 7, 5, 5, 6, 5, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
11, 12, 12, 11, 9, 9, 9, 9, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
11, 12, 11, 11, 9, 9, 9, 9, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0,
};

/***************************************************************************/
/* cpu state */
/***************************************************************************/
Expand All @@ -94,6 +111,7 @@ i8088_cpu_device::i8088_cpu_device(const machine_config &mconfig, const char *ta
: i8086_cpu_device(mconfig, I8088, tag, owner, clock, 8)
{
memcpy(m_timing, m_i8086_timing, sizeof(m_i8086_timing));
memcpy(m_ea_timing, m_i8086_ea_timing, sizeof(m_i8086_ea_timing));
}

i8086_cpu_device::i8086_cpu_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
Expand Down Expand Up @@ -1504,28 +1522,28 @@ bool i8086_common_cpu_device::common_op(uint8_t op)
m_modrm = fetch();
m_src = RegByte();
PutRMByte(m_src);
CLKM(ALU_RR8,ALU_MR8);
CLKM(MOV_RR8,MOV_MR8);
break;

case 0x89: // i_mov_wr16
m_modrm = fetch();
m_src = RegWord();
PutRMWord(m_src);
CLKM(ALU_RR16,ALU_MR16);
CLKM(MOV_RR16,MOV_MR16);
break;

case 0x8a: // i_mov_r8b
m_modrm = fetch();
m_src = GetRMByte();
RegByte(m_src);
CLKM(ALU_RR8,ALU_RM8);
CLKM(MOV_RR8,MOV_RM8);
break;

case 0x8b: // i_mov_r16w
m_modrm = fetch();
m_src = GetRMWord();
RegWord(m_src);
CLKM(ALU_RR16,ALU_RM16);
CLKM(MOV_RR16,MOV_RM16);
break;

case 0x8c: // i_mov_wsreg
Expand Down
2 changes: 2 additions & 0 deletions src/devices/cpu/i86/i86.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -330,6 +330,7 @@ class i8086_common_cpu_device : public cpu_device, public i386_disassembler::con
} m_Mod_RM;

uint8_t m_timing[200];
uint8_t m_ea_timing[200];
bool m_halt;

bool m_lock;
Expand Down Expand Up @@ -372,6 +373,7 @@ class i8086_cpu_device : public i8086_common_cpu_device
address_space_config m_extra_config;
address_space_config m_io_config;
static const uint8_t m_i8086_timing[200];
static const uint8_t m_i8086_ea_timing[200];
devcb_write_line m_out_if_func;
devcb_write32 m_esc_opcode_handler;
devcb_write32 m_esc_data_handler;
Expand Down
28 changes: 3 additions & 25 deletions src/devices/cpu/i86/i86inline.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -76,140 +76,118 @@ inline void i8086_common_cpu_device::CLKM(uint8_t op_reg, uint8_t op_mem)
inline uint32_t i8086_common_cpu_device::get_ea(int size, int op)
{
uint16_t e16;
uint8_t modrm = m_modrm & 0xc7;

switch( m_modrm & 0xc7 )
switch( modrm )
{
case 0x00:
m_icount -= 7;
m_eo = m_regs.w[BX] + m_regs.w[SI];
m_ea = calc_addr(DS, m_eo, size, op);
break;
case 0x01:
m_icount -= 8;
m_eo = m_regs.w[BX] + m_regs.w[DI];
m_ea = calc_addr(DS, m_eo, size, op);
break;
case 0x02:
m_icount -= 8;
m_eo = m_regs.w[BP] + m_regs.w[SI];
m_ea = calc_addr(SS, m_eo, size, op);
break;
case 0x03:
m_icount -= 7;
m_eo = m_regs.w[BP] + m_regs.w[DI];
m_ea = calc_addr(SS, m_eo, size, op);
break;
case 0x04:
m_icount -= 5;
m_eo = m_regs.w[SI];
m_ea = calc_addr(DS, m_eo, size, op);
break;
case 0x05:
m_icount -= 5;
m_eo = m_regs.w[DI];
m_ea = calc_addr(DS, m_eo, size, op);
break;
case 0x06:
m_icount -= 6;
m_eo = fetch_word();
m_ea = calc_addr(DS, m_eo, size, op);
break;
case 0x07:
m_icount -= 5;
m_eo = m_regs.w[BX];
m_ea = calc_addr(DS, m_eo, size, op);
break;

case 0x40:
m_icount -= 11;
m_eo = m_regs.w[BX] + m_regs.w[SI] + (int8_t)fetch();
m_ea = calc_addr(DS, m_eo, size, op);
break;
case 0x41:
m_icount -= 12;
m_eo = m_regs.w[BX] + m_regs.w[DI] + (int8_t)fetch();
m_ea = calc_addr(DS, m_eo, size, op);
break;
case 0x42:
m_icount -= 12;
m_eo = m_regs.w[BP] + m_regs.w[SI] + (int8_t)fetch();
m_ea = calc_addr(SS, m_eo, size, op);
break;
case 0x43:
m_icount -= 11;
m_eo = m_regs.w[BP] + m_regs.w[DI] + (int8_t)fetch();
m_ea = calc_addr(SS, m_eo, size, op);
break;
case 0x44:
m_icount -= 9;
m_eo = m_regs.w[SI] + (int8_t)fetch();
m_ea = calc_addr(DS, m_eo, size, op);
break;
case 0x45:
m_icount -= 9;
m_eo = m_regs.w[DI] + (int8_t)fetch();
m_ea = calc_addr(DS, m_eo, size, op);
break;
case 0x46:
m_icount -= 9;
m_eo = m_regs.w[BP] + (int8_t)fetch();
m_ea = calc_addr(SS, m_eo, size, op);
break;
case 0x47:
m_icount -= 9;
m_eo = m_regs.w[BX] + (int8_t)fetch();
m_ea = calc_addr(DS, m_eo, size, op);
break;

case 0x80:
m_icount -= 11;
e16 = fetch_word();
m_eo = m_regs.w[BX] + m_regs.w[SI] + (int16_t)e16;
m_ea = calc_addr(DS, m_eo, size, op);
break;
case 0x81:
m_icount -= 12;
e16 = fetch_word();
m_eo = m_regs.w[BX] + m_regs.w[DI] + (int16_t)e16;
m_ea = calc_addr(DS, m_eo, size, op);
break;
case 0x82:
m_icount -= 11;
e16 = fetch_word();
m_eo = m_regs.w[BP] + m_regs.w[SI] + (int16_t)e16;
m_ea = calc_addr(SS, m_eo, size, op);
break;
case 0x83:
m_icount -= 11;
e16 = fetch_word();
m_eo = m_regs.w[BP] + m_regs.w[DI] + (int16_t)e16;
m_ea = calc_addr(SS, m_eo, size, op);
break;
case 0x84:
m_icount -= 9;
e16 = fetch_word();
m_eo = m_regs.w[SI] + (int16_t)e16;
m_ea = calc_addr(DS, m_eo, size, op);
break;
case 0x85:
m_icount -= 9;
e16 = fetch_word();
m_eo = m_regs.w[DI] + (int16_t)e16;
m_ea = calc_addr(DS, m_eo, size, op);
break;
case 0x86:
m_icount -= 9;
e16 = fetch_word();
m_eo = m_regs.w[BP] + (int16_t)e16;
m_ea = calc_addr(SS, m_eo, size, op);
break;
case 0x87:
m_icount -= 9;
e16 = fetch_word();
m_eo = m_regs.w[BX] + (int16_t)e16;
m_ea = calc_addr(DS, m_eo, size, op);
break;
}
m_icount -= m_ea_timing[modrm];
return m_ea;
}

Expand Down
Loading