X-Git-Url: http://gitweb.hugovil.com/?a=blobdiff_plain;f=src%2Fcpu8051.c;h=2f22df482d9aa4d487bd311149226c2900294bd8;hb=b23541495010180e3a69e3e1f64c934b28775878;hp=a4e587b94848120e94a937eb5d93feb2a20b3d51;hpb=b1fbb635cdd64e96bf36a62dc6b59d6724f5ad57;p=emu8051.git

diff --git a/src/cpu8051.c b/src/cpu8051.c
index a4e587b..2f22df4 100644
--- a/src/cpu8051.c
+++ b/src/cpu8051.c
@@ -1,11 +1,29 @@
-/* cpu8051.c */
-
+/*
+ * cpu8051.c
+ *
+ * Copyright (C) 1999 Jonathan St-André
+ * Copyright (C) 1999 Hugo Villeneuve <hugo@hugovil.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
 
 /* Define only here, for not having extern scope on local variables. */
 #define CPU8051_M 1
 
-
 #include <stdio.h>
+#include <stdint.h>
 
 #include "reg8051.h"
 #include "cpu8051.h"
@@ -13,422 +31,367 @@
 #include "disasm.h"
 #include "instructions_8051.h"
 
+/* Check if the address is a breakpoint */
+int
+IsBreakpoint(unsigned int address)
+{
+	int k;
+
+	for (k = 0; k < cpu8051.bp_count; k++) {
+		if (cpu8051.bp[k] == address)
+			return 1;
+	}
+
+	/* The address was not found in the list of breakpoints */
+	return 0;
+}
 
+/* Show Breakpoints list */
 void
-cpu8051_init( void )
+ShowBreakpoints(void)
 {
-  cpu8051.pc = 0;
-  cpu8051.clock = 0;
-  cpu8051.active_priority = -1;
-}
+	int k;
 
+	for (k = 0; k < cpu8051.bp_count; k++)
+		printf("Breakpoint at address = %.4X\n", cpu8051.bp[k]);
+}
 
-//////////////////////////////////////////////////////////////////////////////
-// Execute at address cpu8051.pc from PGMMem
-//////////////////////////////////////////////////////////////////////////////
+/* Set Breakpoint at address at the end of the breakpoint list */
 void
-cpu8051_Exec( void )
+SetBreakpoint(unsigned int address)
 {
-  int i;
-  unsigned char opcode;
-  int insttiming;
-
-  opcode = memory_read8( PGM_MEM_ID, cpu8051.pc );
-  cpu8051.pc++;
-  insttiming = (*opcode_table[opcode])(); /* Function callback. */
-  
-  for( i = 0; i < insttiming; i++ ) {
-    cpu8051_CheckInterrupts();
-    cpu8051_DoTimers();
-    cpu8051.clock++;
-  }
+	if (IsBreakpoint(address))
+		return; /* Already a breakpoint */
+
+	if (cpu8051.bp_count < MAXBP)
+		cpu8051.bp[cpu8051.bp_count++] = address;
 }
 
+/* Clear Breakpoint at Address from list */
+void
+ClearBreakpoint(unsigned int address)
+{
+	int k;
+
+	for (k = 0; k < cpu8051.bp_count; k++) {
+		if (cpu8051.bp[k] == address) {
+			/* Fill removed breakpoint slot with last entry */
+			cpu8051.bp[k] = cpu8051.bp[cpu8051.bp_count - 1];
+			cpu8051.bp_count--;
+		}
+	}
+}
 
-//////////////////////////////////////////////////////////////////////////////
-// Return cpu8051.pc + size in bytes of current instruction
-//////////////////////////////////////////////////////////////////////////////
-unsigned int
-cpu8051_GetNextAddress( void )
+/* Toggle the breakpoint at Address. */
+void
+ToggleBreakpoint(unsigned int address)
 {
-#ifdef DECPP
-  return ( cpu8051.pc + InstSizesTbl[ memory_read8( PGM_MEM_ID, cpu8051.pc ) ] );
-#endif
-  return 0; /* temp */
+	if (IsBreakpoint(address))
+		ClearBreakpoint(address);
+	else
+		SetBreakpoint(address);
 }
 
+void
+cpu8051_init(void)
+{
+	cpu8051.pc = 0;
+	cpu8051.clock = 0;
+	cpu8051.active_priority = -1;
+	cpu8051.bp_count = 0;
+}
 
-//////////////////////////////////////////////////////////////////////////////
-// Reset the registers and CPU state
-//////////////////////////////////////////////////////////////////////////////
+/* Reset the registers and CPU state */
 void
-cpu8051_Reset( void )
+cpu8051_Reset(void)
 {
-  cpu8051.pc = 0;
-  cpu8051.clock= 0;
-  cpu8051.active_priority = -1;
+	int i;
 
-  // Reinitialisation des registres
-  int i;
-  for ( i = 0; i < 128; i++ ) {
+	cpu8051.pc = 0;
+	cpu8051.clock = 0;
+	cpu8051.active_priority = -1;
 
-    memory_write8( SFR_MEM_ID, i, 0 );
+	/* Reset registers */
 
-    memory_write8( INT_MEM_ID, i, 0 );
-  }
+	for (i = 0; i < 256; i++) {
+		/* Clear  IRAM nad SFR */
+		memory_write8(INT_MEM_ID, i, 0);
+	}
 
-  memory_write8( SFR_MEM_ID, _P0_ - 0x80, 0xFF );
-  memory_write8( SFR_MEM_ID, _P1_ - 0x80, 0xFF );
-  memory_write8( SFR_MEM_ID, _P2_ - 0x80, 0xFF );
-  memory_write8( SFR_MEM_ID, _P3_ - 0x80, 0xFF );
-  memory_write8( SFR_MEM_ID, _SP_ - 0x80, 0x07 );
+	memory_write8(INT_MEM_ID, _P0_, 0xFF);
+	memory_write8(INT_MEM_ID, _P1_, 0xFF);
+	memory_write8(INT_MEM_ID, _P2_, 0xFF);
+	memory_write8(INT_MEM_ID, _P3_, 0xFF);
+	memory_write8(INT_MEM_ID, _SP_, 0x07);
 }
 
-
-//////////////////////////////////////////////////////////////////////////////
-// Write with a direct addressing mode at Address the new Value
-//////////////////////////////////////////////////////////////////////////////
-void
-cpu8051_WriteD( unsigned int Address, unsigned char Value )
+static void
+cpu8051_convert_bit_address(uint8_t bit_address, uint8_t *byte_address,
+			    uint8_t *bit_number)
 {
-  if ( Address > 0x7F ) {
-    memory_write8( SFR_MEM_ID, Address - 0x80, Value );
-    return;
-  }
-  
-  memory_write8( INT_MEM_ID, Address, Value );
+	if (bit_address > 0x7F) {
+		/* SFR 80-FF */
+		*byte_address = bit_address & 0xF8;
+		*bit_number = bit_address & 0x07;
+	} else {
+		/* 20-2F */
+		*byte_address = (bit_address >> 3) + 0x20;
+		*bit_number = bit_address & 0x07;
+	}
 }
 
-
-//////////////////////////////////////////////////////////////////////////////
-// Ecriture d'une valeur dans la memoire interne ( Address = $00 a $FF )
-//////////////////////////////////////////////////////////////////////////////
+/* Write with a direct addressing mode at Address the new Value */
 void
-cpu8051_WriteInt( unsigned int Address, unsigned char Value )
+cpu8051_WriteD(unsigned int Address, unsigned char Value)
 {
-  if ( Address > 0x7F ) {
-    memory_write8( SFR_MEM_ID, Address - 0x80, Value );
-  }
-  else {
-    memory_write8( INT_MEM_ID, Address, Value );
-  }
-
-  return;
+	memory_write8(INT_MEM_ID, Address, Value);
 }
 
-
-//////////////////////////////////////////////////////////////////////////////
-// Write with an indirect addressing mode at Address the new Value
-//////////////////////////////////////////////////////////////////////////////
+/* Write with an indirect addressing mode at Address the new Value */
 void
-cpu8051_WriteI( unsigned int Address, unsigned char Value )
+cpu8051_WriteI(unsigned int Address, unsigned char Value)
 {
-  if ( Address > 0x7F ) {
-    memory_write8( EXT_MEM_ID, Address, Value );
-    return;
-  }
+	if (Address > 0x7F) {
+		memory_write8(EXT_MEM_ID, Address, Value);
+		return;
+	}
 
-  memory_write8( INT_MEM_ID, Address, Value );
+	memory_write8(INT_MEM_ID, Address, Value);
 }
 
-
-//////////////////////////////////////////////////////////////////////////////
-// Read with a direct addressing mode at Address
-//////////////////////////////////////////////////////////////////////////////
-unsigned char
-cpu8051_ReadD( unsigned int Address )
+/* Write with a bit addressing mode at BitAddress the new Value */
+void
+cpu8051_WriteB(uint8_t bit_address, uint8_t value)
 {
-  if ( Address > 0xFF ) {
-    return memory_read8( EXT_MEM_ID, Address );
-  }
+	uint8_t byte_address;
+	uint8_t bit_number;
+	unsigned char ByteValue, ByteMask;
 
-  if ( Address > 0x7F ) {
-    return memory_read8( SFR_MEM_ID, Address - 0x80 );
-  }
+	cpu8051_convert_bit_address(bit_address, &byte_address, &bit_number);
 
-  return memory_read8( INT_MEM_ID, Address );
+	ByteMask = ((1 << bit_number) ^ 0xFF);
+	ByteValue = cpu8051_ReadD(byte_address) & ByteMask;
+	ByteValue += value << bit_number;
+	cpu8051_WriteD(byte_address, ByteValue);
 }
 
-
-//////////////////////////////////////////////////////////////////////////////
-// Read Internal data memory at Address
-//////////////////////////////////////////////////////////////////////////////
+/* Read with a direct addressing mode at Address */
 unsigned char
-cpu8051_ReadInt( unsigned int Address )
+cpu8051_ReadD(unsigned int Address)
 {
-  if ( Address > 0x7F ) {
-    return memory_read8( SFR_MEM_ID, Address - 0x80 );
-  }
-  else {
-    return memory_read8( INT_MEM_ID, Address );
-  }
+	if (Address > 0xFF)
+		return memory_read8(EXT_MEM_ID, Address);
+	else
+		return memory_read8(INT_MEM_ID, Address);
 }
 
-
-//////////////////////////////////////////////////////////////////////////////
-// unsigned char cpu8051_ReadI( unsigned int Address )
-// Read with a indirect addressing mode at Address
-//////////////////////////////////////////////////////////////////////////////
+/* Read with a indirect addressing mode at Address */
 unsigned char
-cpu8051_ReadI( unsigned int Address )
+cpu8051_ReadI(unsigned int Address)
 {
-  if ( Address > 0x7F ) {
-    return memory_read8( EXT_MEM_ID, Address );
-  }
-  else {
-    return memory_read8( INT_MEM_ID, Address );
-  }
+	if (Address > 0x7F)
+		return memory_read8(EXT_MEM_ID, Address);
+	else
+		return memory_read8(INT_MEM_ID, Address);
 }
 
-
-//////////////////////////////////////////////////////////////////////////////
-// Write with a bit addressing mode at BitAddress the new Value
-//////////////////////////////////////////////////////////////////////////////
-void
-cpu8051_WriteB( unsigned int BitAddress, unsigned char Value )
+/* Read with a bit addressing mode at BitAddress */
+unsigned char
+cpu8051_ReadB(uint8_t bit_address)
 {
-  unsigned int ByteAddress, BitNumber;
-  unsigned char ByteValue, ByteMask;
-
-  if ( BitAddress > 0x7F ) {
-    // SFR 80-FF
-    ByteAddress = BitAddress & 0xF8;
-    BitNumber = BitAddress & 0x07;
-  }
-  else {
-    // 20-2F
-    ByteAddress = ( BitAddress >> 3 ) + 0x20;
-    BitNumber = BitAddress & 0x07;
-  }
-  ByteMask = ( ( 1 << BitNumber ) ^ 0xFF );
-  ByteValue = cpu8051_ReadD( ByteAddress ) & ByteMask;
-  ByteValue += Value << BitNumber;
-  cpu8051_WriteD( ByteAddress, ByteValue );
-}
+	uint8_t byte_address;
+	uint8_t bit_number;
+	unsigned char BitValue;
 
+	cpu8051_convert_bit_address(bit_address, &byte_address, &bit_number);
 
-//////////////////////////////////////////////////////////////////////////////
-// Read with a bit addressing mode at BitAddress
-//////////////////////////////////////////////////////////////////////////////
-unsigned char
-cpu8051_ReadB( unsigned int BitAddress )
+	BitValue = (cpu8051_ReadD(byte_address) >> bit_number);
+	BitValue &= 1;
+	return BitValue;
+}
+
+static void
+cpu8051_process_interrupt(int pc, int pri)
 {
-  unsigned int ByteAddress, BitNumber;
-  unsigned char BitValue;
-
-  if ( BitAddress > 0x7F ) {
-    // SFR 80-FF
-    ByteAddress = BitAddress & 0xF8;
-    BitNumber = BitAddress & 0x07;
-  }
-  else {
-    // 20-2F
-    ByteAddress = ( BitAddress >> 3 ) + 0x20;
-    BitNumber = BitAddress & 0x07;
-  }
-  BitValue = ( cpu8051_ReadD( ByteAddress ) >> BitNumber );
-  BitValue &= 1;
-  return BitValue;
+	unsigned char SP;
+
+	SP = cpu8051_ReadD(_SP_);
+	cpu8051_WriteI(++SP, (cpu8051.pc & 0xFF));
+	cpu8051_WriteI(++SP, (cpu8051.pc >> 8));
+	cpu8051_WriteD(_SP_, SP);
+	cpu8051.pc = 0x0B;
+	cpu8051.active_priority = pri;
 }
 
 
-//////////////////////////////////////////////////////////////////////////////
-// Check interrupts state and process them as needed
-//////////////////////////////////////////////////////////////////////////////
-void
-cpu8051_CheckInterrupts()
+/* Check interrupts state and process them as needed */
+static void
+cpu8051_CheckInterrupts(void)
 {
-  unsigned char SP;
-  int i;
-
-  if ( cpu8051_ReadD( _IE_ ) & 0x80 ) {
-    for ( i = 1; i >= 0; i-- )
-      if ( cpu8051.active_priority < i ) {
-	//-------------------------  External interrupt 0 ----------------------------     
-	//        if ( ( cpu8051_ReadD( _IE_ ) & 0x01 ) && ( ( cpu8051_ReadD( _IP_ ) & 0x01 ) ? i : !i ) && pin0 )
-	//-------------------------- Interrupt timer 0 -------------------------------
-	if ( ( cpu8051_ReadD( _IE_ ) & 0x02 ) && ( ( cpu8051_ReadD( _IP_ & 0x02 ) ? i : !i ) && ( cpu8051_ReadD( _TCON_ ) & 0x20 ) ) ){
-	  cpu8051_WriteD( _TCON_, cpu8051_ReadD( _TCON_ ) & 0xDF );
-	  SP = cpu8051_ReadD( _SP_ );
-	  cpu8051_WriteI( ++SP, ( cpu8051.pc & 0xFF ) );
-	  cpu8051_WriteI( ++SP, ( cpu8051.pc >> 8 ) );
-	  cpu8051_WriteD( _SP_, SP );
-	  cpu8051.pc = 0x0B;  
-	  cpu8051.active_priority = i;
-	  return;          
-	}
-	//-------------------------- External interrupt 1 ----------------------------     
-	//        if ( ( cpu8051_ReadD( _IE_ ) & 0x04 ) && ( ( cpu8051_ReadD( _IP_ ) & 0x04 ) ? i : !i ) && pin1 )
-	//-------------------------- Interrupt timer 1 -------------------------------      
-	if ( ( cpu8051_ReadD( _IE_ ) & 0x08 ) && ( ( cpu8051_ReadD( _IP_ ) & 0x08 ) ? i : !i ) && ( cpu8051_ReadD( _TCON_ ) & 0x80 ) ) {
-	  cpu8051_WriteD( _TCON_, cpu8051_ReadD( _TCON_ ) & 0x7F );
-	  SP = cpu8051_ReadD( _SP_ );
-	  cpu8051_WriteI( ++SP, ( cpu8051.pc & 0xFF ) );
-	  cpu8051_WriteI( ++SP, ( cpu8051.pc >> 8 ) );
-	  cpu8051_WriteD( _SP_, SP );
-	  cpu8051.pc = 0x1B;
-	  cpu8051.active_priority = i;
-	  return;
+	int i;
+
+	if ((cpu8051_ReadD(_IE_) & 0x80) == 0)
+		return;
+
+	for (i = 1; i >= 0; i--) {
+		if (cpu8051.active_priority < i) {
+			/* Interrupt timer 0 */
+			if ((cpu8051_ReadD(_IE_) & 0x02) &&
+			    ((cpu8051_ReadD(_IP_ & 0x02) ? i : !i) &&
+			     (cpu8051_ReadD(_TCON_) & 0x20))) {
+				cpu8051_WriteD(_TCON_,
+					       cpu8051_ReadD(_TCON_) & 0xDF);
+				cpu8051_process_interrupt(0x0B, i);
+				return;
+			}
+			/* Interrupt timer 1 */
+			if ((cpu8051_ReadD(_IE_) & 0x08) &&
+			    ((cpu8051_ReadD(_IP_) & 0x08) ? i : !i) &&
+			    (cpu8051_ReadD(_TCON_) & 0x80)) {
+				cpu8051_WriteD(_TCON_,
+					       cpu8051_ReadD(_TCON_) & 0x7F);
+				cpu8051_process_interrupt(0x1B, i);
+				return;
+			}
+			/* Serial Interrupts */
+			if ((cpu8051_ReadD(_IE_) & 0x10) &&
+			    ((cpu8051_ReadD(_IP_) & 0x10) ? i : !i) &&
+			    (cpu8051_ReadD(_SCON_) & 0x03)) {
+				cpu8051_process_interrupt(0x23, i);
+				return;
+			}
+			/* Interrupt timer 2 */
+			if ((cpu8051_ReadD(_IE_) & 0x20) &&
+			    ((cpu8051_ReadD(_IP_) & 0x20) ? i : !i) &&
+			    (cpu8051_ReadD(_T2CON_) & 0x80)) {
+				cpu8051_process_interrupt(0x2B, i);
+				return;
+			}
+		}
 	}
-	//-------------------------- Serial Interrupts -------------------------------
-	if ( ( cpu8051_ReadD( _IE_ ) & 0x10 ) && ( ( cpu8051_ReadD( _IP_ ) & 0x10 ) ? i : !i ) && ( cpu8051_ReadD( _SCON_ ) & 0x03 ) ) {
-	  SP = cpu8051_ReadD( _SP_ );
-	  cpu8051_WriteI( ++SP, ( cpu8051.pc & 0xFF ) );
-	  cpu8051_WriteI( ++SP, ( cpu8051.pc >> 8 ) );
-	  cpu8051_WriteD( _SP_, SP );
-	  cpu8051.pc = 0x23;
-	  cpu8051.active_priority = i;
-	  return;
-	}
-	//-------------------------- Interrupt timer 2 -------------------------------
-	if ( ( cpu8051_ReadD( _IE_ ) & 0x20 ) && ( ( cpu8051_ReadD( _IP_ ) & 0x20 ) ? i : !i ) && ( cpu8051_ReadD( _T2CON_ ) & 0x80 ) ) {          
-	  SP = cpu8051_ReadD( _SP_ );
-	  cpu8051_WriteI( ++SP, ( cpu8051.pc & 0xFF ) );
-	  cpu8051_WriteI( ++SP, ( cpu8051.pc >> 8 ) );
-	  cpu8051_WriteD( _SP_, SP );
-	  cpu8051.pc = 0x2B;
-	  cpu8051.active_priority = i;
-	  return;
+}
+
+static void
+process_timer(uint8_t tl, uint8_t th, uint8_t tf_mask, uint8_t TR, uint8_t mode,
+	      uint8_t GATE, uint32_t TimerCounter)
+{
+	unsigned int tmp;
+
+	switch (mode) {
+	case 0:
+		/* Mode 0, 13-bits counter. */
+		tmp = cpu8051_ReadD(th) * 0x100 + cpu8051_ReadD(tl);
+		tmp++;
+		tmp &= 0x1FFF; /* We keep only 13 bits */
+
+		if (tmp == 0)  /* If overflow set TF0 */
+			cpu8051_WriteD(_TCON_, cpu8051_ReadD(_TCON_) | tf_mask);
+		cpu8051_WriteD(_TH0_, tmp / 0x100);
+		cpu8051_WriteD(_TL0_, tmp & 0xFF);
+		break;
+	case 1:
+		/* Mode 1, 16-bits counter */
+		tmp = cpu8051_ReadD(th) * 0x100 + cpu8051_ReadD(tl);
+		tmp++;
+		tmp &= 0xFFFF; /* We keep only 16 bits */
+		if (tmp == 0) /* If overflow set TF0 */
+			cpu8051_WriteD(_TCON_, cpu8051_ReadD(_TCON_) | tf_mask);
+		cpu8051_WriteD(_TH0_, (tmp / 0x100));
+		cpu8051_WriteD(_TL0_, (tmp & 0xFF));
+		break;
+	case 2:
+		/* Mode 2, 8-bits counter with Auto-Reload */
+		tmp = cpu8051_ReadD(tl);
+		tmp++;
+		tmp &= 0xFF;
+		if (tmp == 0) {
+			/* If overflow -> reload and set TF0 */
+			cpu8051_WriteD(_TCON_, cpu8051_ReadD(_TCON_) | tf_mask);
+			cpu8051_WriteD(tl, cpu8051_ReadD(th));
+		} else
+			cpu8051_WriteD(tl, tmp);
+		break;
+	case 3:
+		/* Mode 3 : inactive mode for timer 1 */
+		if (tl == _TL0_) {
+			/* TL0 and TH0 are 2 independents 8-bits timers. */
+			if (TR && !GATE && !TimerCounter) {
+				tmp = cpu8051_ReadD(tl);
+				tmp++;
+				tmp &= 0xFF;
+				if (tmp == 0) /* If TL0 overflow set TF0 */
+					cpu8051_WriteD(_TCON_,
+						       cpu8051_ReadD(_TCON_) |
+						       tf_mask);
+				cpu8051_WriteD(tl, tmp);
+			} /* TH0 utilise TR1 et TF1. */
+			TR = cpu8051_ReadD(_TCON_) & 0x40;
+			if (TR) {
+				tmp = cpu8051_ReadD(th);
+				tmp++;
+				tmp &= 0xFF;
+				if (tmp == 0) /* If TH0 overflow set TF1 */
+					cpu8051_WriteD(_TCON_,
+						       cpu8051_ReadD(_TCON_) |
+						       0x80);
+				cpu8051_WriteD(_TH0_, tmp);
+			}
+		}
+		break;
 	}
-      }
-  }
 }
 
+/* Run timers */
+static void
+cpu8051_DoTimers(void)
+{
+	unsigned int TR;
+	unsigned int MODE;
+	unsigned int GATE;
+	unsigned int TimerCounter;
+
+	/* Timer 0 */
+	TR = cpu8051_ReadD(_TCON_) & 0x10;
+	MODE = cpu8051_ReadD(_TMOD_) & 0x03;
+	GATE = cpu8051_ReadD(_TMOD_) & 0x08;
+	TimerCounter = cpu8051_ReadD(_TMOD_) & 0x04;
+
+	if ((TR && !GATE && !TimerCounter) || (MODE == 3))
+		process_timer(_TL0_, _TH0_, 0x20, TR, MODE, GATE, TimerCounter);
+
+	/* Timer 1 */
+	TR = cpu8051_ReadD(_TCON_) & 0x40;
+	MODE = (cpu8051_ReadD(_TMOD_) & 0x30) >> 4 ;
+	GATE = cpu8051_ReadD(_TMOD_) & 0x80;
+	TimerCounter = cpu8051_ReadD(_TMOD_) & 0x40;
+
+	if (TR && !GATE && !TimerCounter)
+		process_timer(_TL1_, _TH1_, 0x80, TR, MODE, GATE, TimerCounter);
+}
 
-//////////////////////////////////////////////////////////////////////////////
-// Execute les timers
-//////////////////////////////////////////////////////////////////////////////
+/* Execute at address cpu8051.pc from PGMMem */
 void
-cpu8051_DoTimers( )
+cpu8051_Exec(void)
 {
-  unsigned int tmp;
-  unsigned int TR;
-  unsigned int MODE;
-  unsigned int GATE;
-  unsigned int TimerCounter;
-
-  // ----- Timer 0
-  TR = cpu8051_ReadD( _TCON_ ) & 0x10;
-  MODE = cpu8051_ReadD( _TMOD_ ) & 0x03;
-  GATE = cpu8051_ReadD( _TMOD_ ) & 0x08;
-  TimerCounter = cpu8051_ReadD( _TMOD_ ) & 0x04;
-  
-  if ( ( TR && !GATE && !TimerCounter ) || ( MODE == 3 ) )
-    switch( MODE ) {
-      // Mode 0, compteur de 13 bits.
-    case 0 :
-      tmp = cpu8051_ReadD( _TH0_ ) * 0x100 + cpu8051_ReadD( _TL0_ );
-
-      tmp++;
-      tmp &= 0x1FFF;   // On ne garde que 13 bits.
-
-      if ( tmp == 0 )    // If overflow set TF0
-	cpu8051_WriteD( _TCON_, cpu8051_ReadD( _TCON_ ) | 0x20 );
-      cpu8051_WriteD( _TH0_, tmp / 0x100 );
-      cpu8051_WriteD( _TL0_, tmp & 0xFF  );
-      break;
-      
-      // Mode 1, compteur de 16 bits.
-    case 1 :
-      tmp = cpu8051_ReadD( _TH0_ ) * 0x100 + cpu8051_ReadD( _TL0_ );
-      tmp++;
-      tmp &= 0xFFFF;   // On ne garde que 16 bits.
-      if ( tmp == 0 )   // If overflow set TF0
-	cpu8051_WriteD( _TCON_, cpu8051_ReadD( _TCON_ ) | 0x20 );
-      cpu8051_WriteD( _TH0_, ( tmp / 0x100 ) );
-      cpu8051_WriteD( _TL0_, ( tmp & 0xFF ) );
-      break;
-      
-      // Mode 2, Compteur de 8 bits avec Auto-Reload
-    case 2 :
-      tmp = cpu8051_ReadD( _TL0_ );
-      tmp++;
-      tmp &= 0xFF;
-      if ( tmp == 0 ) {    // If overflow -> reload et set TF0
-	cpu8051_WriteD( _TCON_, cpu8051_ReadD( _TCON_ ) | 0x20 );
-	cpu8051_WriteD( _TL0_, cpu8051_ReadD( _TH0_ ) );
-      }
-      else
-	cpu8051_WriteD( _TL0_, tmp );
-      break;
-    
-    // Mode 3 : TL0 et TH0 sont 2 Timers independants de 8 bits chacuns.
-    case 3 :
-      if ( TR && !GATE && !TimerCounter ) {
-	tmp = cpu8051_ReadD( _TL0_ );
-	tmp++;
-	tmp &= 0xFF;
-	if ( tmp == 0 )  // If TL0 overflow set TF0
-	  cpu8051_WriteD( _TCON_, cpu8051_ReadD( _TCON_ ) | 0x20 );
-	cpu8051_WriteD( _TL0_, tmp );
-      }  // TH0 utilise TR1 et TF1.
-      TR = cpu8051_ReadD( _TCON_ ) & 0x40;
-      if ( TR ) {
-	tmp = cpu8051_ReadD( _TH0_ );
-	tmp++;
-	tmp &= 0xFF;
-	if ( tmp == 0 )  // If TH0 overflow set TF1
-	  cpu8051_WriteD( _TCON_, cpu8051_ReadD( _TCON_ ) | 0x80 );  // TF1 = 1.
-	cpu8051_WriteD( _TH0_, tmp );
-      }
-      break;
-    };
-  
-
-  // ----- Timer 1
-  TR = cpu8051_ReadD( _TCON_ ) & 0x40;
-  MODE = ( cpu8051_ReadD( _TMOD_ ) & 0x30 ) >> 4 ;
-  GATE = cpu8051_ReadD( _TMOD_ ) & 0x80;
-  TimerCounter = cpu8051_ReadD( _TMOD_ ) & 0x40;
-  
-  if ( TR && !GATE && !TimerCounter )
-    switch( MODE ) {
-      // Mode 0, compteur de 13 bits.
-    case 0 :
-      tmp = cpu8051_ReadD( _TH1_ ) * 0x100 + cpu8051_ReadD( _TL1_ );
-      tmp++;
-      tmp &= 0x1FFF;   // On ne garde que 13 bits.
-      if ( tmp == 0 )    // If overflow set TF1
-	cpu8051_WriteD( _TCON_, cpu8051_ReadD( _TCON_ ) | 0x80 );
-      cpu8051_WriteD( _TH1_, tmp / 0x100 );
-      cpu8051_WriteD( _TL1_, tmp & 0xFF  );
-      break;
-      
-      // Mode 1, compteur de 16 bits.
-    case 1 :
-      tmp = cpu8051_ReadD( _TH1_ ) * 0x100 + cpu8051_ReadD( _TL1_ );
-      tmp++;
-      tmp &= 0xFFFF;   // On ne garde que 16 bits.
-      if ( tmp == 0 )   // If overflow set TF1
-	cpu8051_WriteD( _TCON_, cpu8051_ReadD( _TCON_ ) | 0x80 );
-      cpu8051_WriteD( _TH1_, ( tmp / 0x100 ) );
-      cpu8051_WriteD( _TL1_, ( tmp & 0xFF ) );
-      break;
-      
-      // Mode 2, Compteur de 8 bits avec Auto-Reload
-    case 2 :
-      tmp = cpu8051_ReadD( _TL1_ );
-      tmp++;
-      tmp &= 0xFF;
-      if ( tmp == 0 ) {    // If overflow -> reload et set TF1
-	cpu8051_WriteD( _TCON_, cpu8051_ReadD( _TCON_ ) | 0x80 );
-	cpu8051_WriteD( _TL1_, cpu8051_ReadD( _TH1_ ) );
-      }
-      else
-	cpu8051_WriteD( _TL1_, tmp );
-      break;
-      
-      // Mode 3 : mode inactif: retient la valeur de TH1 et TL1.
-      // Equivalent a TR1 = 0.
-    case 3 :
-      break;
-      
-    };
+	int i;
+	unsigned char opcode;
+	int insttiming;
+
+	opcode = memory_read8(PGM_MEM_ID, cpu8051.pc);
+	cpu8051.pc++;
+	insttiming = (*opcode_table[opcode])(); /* Function callback. */
+
+	for (i = 0; i < insttiming; i++) {
+		cpu8051_CheckInterrupts();
+		cpu8051_DoTimers();
+		cpu8051.clock++;
+	}
 }
 
-
-// Addressing modes defined in the order as they appear in disasm.hpp
-// from table argstext[]
+/*
+ * Addressing modes defined in the order as they appear in disasm.hpp
+ * from table argstext[]
+ */
 #define ADDR11 0
 #define ADDR16 1
 #define DIRECT 3
@@ -438,184 +401,196 @@ cpu8051_DoTimers( )
 #define DATA16 22
 #define CBITADDR 23
 
-// SFR Memory map [80h - FFh]
-// ---------------------------------------------------------------
-// F8 |      |      |      |      |      |      |      |      | FF
-// F0 |   B  |      |      |      |      |      |      |      | F7
-// E8 |      |      |      |      |      |      |      |      | EF
-// E0 |  ACC |      |      |      |      |      |      |      | E7
-// D8 |      |      |      |      |      |      |      |      | DF
-// D0 |  PSW |      |      |      |      |      |      |      | D7
-// C8 | T2CON|      |RCAP2L|RCAP2H|  TL2 |  TH2 |      |      | CF
-// C0 |      |      |      |      |      |      |      |      | C7
-// B8 |  IP  |      |      |      |      |      |      |      | BF
-// B0 |  P3  |      |      |      |      |      |      |      | B7
-// A8 |  IE  |      |      |      |      |      |      |      | AF
-// A0 |  P2  |      |      |      |      |      |      |      | A7
-// 98 | SCON | SBUF |      |      |      |      |      |      | 9F
-// 90 |  P1  |      |      |      |      |      |      |      | 97
-// 88 | TCON | TMOD |  TL0 |  TL1 |  TH0 |  TH1 |      |      | 8F
-// 80 |  P0  |  SP  |  DPL |  DPH |      |      |      | PCON | 87
-// ---------------------------------------------------------------
-
-
-//////////////////////////////////////////////////////////////////////////////
-// Return as Text the name of the SFR register at Address if any
-//////////////////////////////////////////////////////////////////////////////
-int
-cpu8051_SFRMemInfo( unsigned int Address, char *Text )
+/*
+ * SFR Memory map [80h - FFh]
+ * ---------------------------------------------------------------
+ * F8 |      |      |      |      |      |      |      |      | FF
+ * F0 |   B  |      |      |      |      |      |      |      | F7
+ * E8 |      |      |      |      |      |      |      |      | EF
+ * E0 |  ACC |      |      |      |      |      |      |      | E7
+ * D8 |      |      |      |      |      |      |      |      | DF
+ * D0 |  PSW |      |      |      |      |      |      |      | D7
+ * C8 | T2CON|      |RCAP2L|RCAP2H|  TL2 |  TH2 |      |      | CF
+ * C0 |      |      |      |      |      |      |      |      | C7
+ * B8 |  IP  |      |      |      |      |      |      |      | BF
+ * B0 |  P3  |      |      |      |      |      |      |      | B7
+ * A8 |  IE  |      |      |      |      |      |      |      | AF
+ * A0 |  P2  |      |      |      |      |      |      |      | A7
+ * 98 | SCON | SBUF |      |      |      |      |      |      | 9F
+ * 90 |  P1  |      |      |      |      |      |      |      | 97
+ * 88 | TCON | TMOD |  TL0 |  TL1 |  TH0 |  TH1 |      |      | 8F
+ * 80 |  P0  |  SP  |  DPL |  DPH |      |      |      | PCON | 87
+ * ---------------------------------------------------------------
+ */
+
+/* Return as Text the name of the SFR register at Address if any */
+static int
+cpu8051_SFRMemInfo(unsigned int Address, char *Text)
 {
-  switch( Address ) {
-  case 0x80 : return sprintf( Text, "P0" );
-  case 0x81 : return sprintf( Text, "SP" );
-  case 0x82 : return sprintf( Text, "DPL" );
-  case 0x83 : return sprintf( Text, "DPH" );
-  case 0x87 : return sprintf( Text, "PCON" );
-  case 0x88 : return sprintf( Text, "TCON" );
-  case 0x89 : return sprintf( Text, "TMOD" );
-  case 0x8A : return sprintf( Text, "TL0" );
-  case 0x8B : return sprintf( Text, "TL1" );
-  case 0x8C : return sprintf( Text, "TH0" );
-  case 0x8D : return sprintf( Text, "TH1" );
-  case 0x90 : return sprintf( Text, "P1" );
-  case 0x98 : return sprintf( Text, "SCON" );
-  case 0x99 : return sprintf( Text, "SBUF" );
-  case 0xA0 : return sprintf( Text, "P2" );
-  case 0xA8 : return sprintf( Text, "IE" );
-  case 0xB0 : return sprintf( Text, "P3" );
-  case 0xB8 : return sprintf( Text, "IP" );
-  case 0xC8 : return sprintf( Text, "T2CON" );
-  case 0xCA : return sprintf( Text, "RCAP2L" );
-  case 0xCB : return sprintf( Text, "RCAP2H" );
-  case 0xCC : return sprintf( Text, "TL2" );
-  case 0xCD : return sprintf( Text, "TH2" );
-  case 0xD0 : return sprintf( Text, "PSW" );
-  case 0xE0 : return sprintf( Text, "ACC" );
-  case 0xF0 : return sprintf( Text, "B" );
-  default : return sprintf( Text, "%.2XH", Address );
-  }
+	switch (Address) {
+	case 0x80: return sprintf(Text, "P0");
+	case 0x81: return sprintf(Text, "SP");
+	case 0x82: return sprintf(Text, "DPL");
+	case 0x83: return sprintf(Text, "DPH");
+	case 0x87: return sprintf(Text, "PCON");
+	case 0x88: return sprintf(Text, "TCON");
+	case 0x89: return sprintf(Text, "TMOD");
+	case 0x8A: return sprintf(Text, "TL0");
+	case 0x8B: return sprintf(Text, "TL1");
+	case 0x8C: return sprintf(Text, "TH0");
+	case 0x8D: return sprintf(Text, "TH1");
+	case 0x90: return sprintf(Text, "P1");
+	case 0x98: return sprintf(Text, "SCON");
+	case 0x99: return sprintf(Text, "SBUF");
+	case 0xA0: return sprintf(Text, "P2");
+	case 0xA8: return sprintf(Text, "IE");
+	case 0xB0: return sprintf(Text, "P3");
+	case 0xB8: return sprintf(Text, "IP");
+	case 0xC8: return sprintf(Text, "T2CON");
+	case 0xCA: return sprintf(Text, "RCAP2L");
+	case 0xCB: return sprintf(Text, "RCAP2H");
+	case 0xCC: return sprintf(Text, "TL2");
+	case 0xCD: return sprintf(Text, "TH2");
+	case 0xD0: return sprintf(Text, "PSW");
+	case 0xE0: return sprintf(Text, "ACC");
+	case 0xF0: return sprintf(Text, "B");
+	default: return sprintf(Text, "%.2XH", Address);
+	}
 }
 
-
-//////////////////////////////////////////////////////////////////////////////
-// Return as Text the decoded BitAddress
-//////////////////////////////////////////////////////////////////////////////
-void
-cpu8051_IntMemBitInfo( unsigned int BitAddress, char *Text )
+/* Return as Text the decoded BitAddress */
+static void
+cpu8051_IntMemBitInfo(uint8_t bit_address, char *text)
 {
-  unsigned int ByteAddress, BitNumber;
-  int TextLength;
-  
-  if ( BitAddress > 0x7F ) {
-    // SFR 80-FF
-    ByteAddress = BitAddress & 0xF8;
-    BitNumber = BitAddress & 0x07;
-  }
-  else {
-    // 20-2F
-    ByteAddress = ( BitAddress >> 3 ) + 0x20;
-    BitNumber = BitAddress & 0x07;
-  }
-  
-  TextLength = cpu8051_SFRMemInfo( ByteAddress, Text );
-  // sprintf( &Text[ TextLength ], ".%X" );
-  // Modified by Hugo Villeneuve to remove compilation warning
-  sprintf( &Text[ TextLength ], ".%X", BitAddress );
-}
+	uint8_t byte_address;
+	uint8_t bit_number;
+	int len;
+
+	cpu8051_convert_bit_address(bit_address, &byte_address, &bit_number);
 
+	len = cpu8051_SFRMemInfo(byte_address, text);
+	sprintf(&text[len], ".%X", bit_address);
+}
 
-//////////////////////////////////////////////////////////////////////////////
-// Disasm one instruction at Address into a Text string
-//////////////////////////////////////////////////////////////////////////////
+/* Disasm one instruction at Address into a Text string */
 int
-cpu8051_Disasm( unsigned int Address, char *Text )
+cpu8051_Disasm(unsigned int Address, char *Text)
 {
-  int TextLength=0;
-  char TextTmp[20];
-  unsigned char OpCode;
-  int ArgTblOfs;
-  int InstSize;
-  int i;
-  
-  OpCode = memory_read8( PGM_MEM_ID, Address );
-  InstSize = InstSizesTbl[ OpCode ];
-  //printf("%.4X\n", Address);
-  
-  TextLength += sprintf( Text, " %.4X ", Address );
-  
-  for (i = 0; i < InstSize; i++ )
-    TextLength += sprintf( &Text[TextLength], " %.2X", memory_read8( PGM_MEM_ID, Address + i ) );
-  
-  Address++;
-  
-  for (; TextLength < 17; ) TextLength += sprintf( &Text[ TextLength ], " " );
-  
-  TextLength += sprintf( &Text[ TextLength ], "%s ", InstTextTbl[ InstTypesTbl[ OpCode ] ] );
-  ArgTblOfs = OpCode << 2;
-  
-  for (; TextLength < 25; ) TextLength += sprintf( &Text[ TextLength ], " " );
-  
-  // MOV direct, direct (OpCode 85h) is peculiar, the operands are inverted
-  if ( OpCode == 0x85 ) {
-    cpu8051_SFRMemInfo( memory_read8( PGM_MEM_ID, Address + 1 ), TextTmp );
-    TextLength += sprintf( &Text[ TextLength ], "%s,", TextTmp );
-    cpu8051_SFRMemInfo( memory_read8( PGM_MEM_ID, Address ), TextTmp );
-    TextLength += sprintf( &Text[ TextLength ], "%s", TextTmp );
-    Address += 2;
-    return InstSize;
-  }
-  
-  for ( i = 1; i <= InstArgTbl[ ArgTblOfs ]; i++ ) {
-    switch( InstArgTbl[ ArgTblOfs + i ] ) {
-    case ADDR11  : {
-      TextLength += sprintf( &Text[ TextLength ], "%.4XH", ( ( OpCode << 3) & 0xF00 ) + ( memory_read8( PGM_MEM_ID, Address ) ) );
-      Address++;
-      break;
-    }
-    case ADDR16  : {
-      TextLength += sprintf( &Text[ TextLength ], "%.4XH", ( ( memory_read8( PGM_MEM_ID, Address ) << 8 ) + memory_read8( PGM_MEM_ID, Address + 1 ) ) );
-      Address += 2;
-      break;
-    }
-    case DIRECT  : {
-      cpu8051_SFRMemInfo( memory_read8( PGM_MEM_ID, Address ), TextTmp );
-      TextLength += sprintf( &Text[ TextLength ], "%s", TextTmp );
-      Address++;
-      break;
-    }
-    case BITADDR : {
-      cpu8051_IntMemBitInfo( ( memory_read8( PGM_MEM_ID, Address ) & 0xF8 ), TextTmp );
-      TextLength += sprintf( &Text[ TextLength ], "%s.%X" , TextTmp, ( memory_read8( PGM_MEM_ID, Address ) & 7 ) );
-      Address++;
-      break;
-    }
-    case RELADDR : {
-      Address++;
-      TextLength += sprintf( &Text[ TextLength ], "%.4XH", ( Address & 0xFF00 ) + ( ( ( Address & 0xFF ) + memory_read8( PGM_MEM_ID, Address - 1 ) ) & 0xFF ) );
-      break;
-    }
-    case DATAIMM : {
-      TextLength += sprintf( &Text[ TextLength ], "#%.2XH", memory_read8( PGM_MEM_ID, Address ) );
-      Address++;
-      break;
-    }
-    case DATA16  : {
-      TextLength += sprintf( &Text[ TextLength ],"#%.4XH", ( ( memory_read8( PGM_MEM_ID, Address ) << 8 ) + memory_read8( PGM_MEM_ID, Address+1 ) ) );
-      Address += 2;
-      break;
-    }
-    case CBITADDR : {
-      cpu8051_IntMemBitInfo( ( memory_read8( PGM_MEM_ID, Address ) & 0xF8 ), TextTmp );
-      TextLength += sprintf( &Text[ TextLength ], "/%s.%X", TextTmp, ( memory_read8( PGM_MEM_ID, Address ) & 7 ) );
-      Address++;
-      break;
-    }
-    default : {
-      TextLength += sprintf( &Text[ TextLength ],"%s", ArgsTextTbl[ InstArgTbl[ ArgTblOfs + i ] ] );
-    }
-    }
-    if (i < InstArgTbl[ ArgTblOfs ]) { TextLength += sprintf( &Text[ TextLength ], "," ); }
-  }
-
-  return InstSize;
+	int len = 0;
+	char TextTmp[20];
+	unsigned char OpCode;
+	int ArgTblOfs;
+	int InstSize;
+	int i;
+
+	OpCode = memory_read8(PGM_MEM_ID, Address);
+	InstSize = InstSizesTbl[OpCode];
+
+	len += sprintf(Text, " %.4X ", Address);
+
+	for (i = 0; i < InstSize; i++)
+		len += sprintf(&Text[len], " %.2X",
+				      memory_read8(PGM_MEM_ID, Address + i));
+
+	Address++;
+
+	for (; len < 17;)
+		len += sprintf(&Text[len], " ");
+
+	len += sprintf(&Text[len], "%s ",
+			      InstTextTbl[InstTypesTbl[OpCode]]);
+	ArgTblOfs = OpCode << 2;
+
+	for (; len < 25;)
+		len += sprintf(&Text[len], " ");
+
+	/*
+	 * MOV direct, direct (OpCode 85h) is peculiar, the operands
+	 * are inverted
+	 */
+	if (OpCode == 0x85) {
+		cpu8051_SFRMemInfo(memory_read8(PGM_MEM_ID, Address + 1),
+				   TextTmp);
+		len += sprintf(&Text[len], "%s,", TextTmp);
+		cpu8051_SFRMemInfo(memory_read8(PGM_MEM_ID, Address),
+				   TextTmp);
+		len += sprintf(&Text[len], "%s", TextTmp);
+		Address += 2;
+		return InstSize;
+	}
+
+	for (i = 1; i <= InstArgTbl[ArgTblOfs]; i++) {
+		switch (InstArgTbl[ArgTblOfs + i]) {
+		case ADDR11: {
+			len += sprintf(&Text[len],
+				       "%.4XH", ((OpCode << 3) & 0xF00) +
+				       (memory_read8(PGM_MEM_ID, Address)));
+			Address++;
+			break;
+		}
+		case ADDR16: {
+			len += sprintf(
+				&Text[len], "%.4XH",
+				((memory_read8(PGM_MEM_ID, Address) << 8) +
+				 memory_read8(PGM_MEM_ID, Address + 1)));
+			Address += 2;
+			break;
+		}
+		case DIRECT: {
+			cpu8051_SFRMemInfo(memory_read8(PGM_MEM_ID, Address),
+					   TextTmp);
+			len += sprintf(&Text[len], "%s", TextTmp);
+			Address++;
+			break;
+		}
+		case BITADDR: {
+			cpu8051_IntMemBitInfo(
+				(memory_read8(PGM_MEM_ID, Address) & 0xF8),
+				TextTmp);
+			len += sprintf(&Text[len], "%s.%X" , TextTmp,
+				       (memory_read8(PGM_MEM_ID, Address) & 7));
+			Address++;
+			break;
+		}
+		case RELADDR: {
+			Address++;
+			len += sprintf(&Text[len], "%.4XH", (Address & 0xFF00) +
+				       (((Address & 0xFF) +
+					 memory_read8(PGM_MEM_ID,
+						      Address - 1)) & 0xFF));
+			break;
+		}
+		case DATAIMM: {
+			len += sprintf(&Text[len], "#%.2XH",
+				       memory_read8(PGM_MEM_ID, Address));
+			Address++;
+			break;
+		}
+		case DATA16: {
+			len += sprintf(&Text[len], "#%.4XH",
+				       ((memory_read8(PGM_MEM_ID,
+						      Address) << 8) +
+					memory_read8(PGM_MEM_ID, Address+1)));
+			Address += 2;
+			break;
+		}
+		case CBITADDR: {
+			cpu8051_IntMemBitInfo((memory_read8(PGM_MEM_ID,
+							    Address) & 0xF8),
+					      TextTmp);
+			len += sprintf(&Text[len], "/%s.%X", TextTmp,
+				       (memory_read8(PGM_MEM_ID, Address) & 7));
+			Address++;
+			break;
+		}
+		default: {
+			len += sprintf(&Text[len], "%s",
+				       ArgsTextTbl[InstArgTbl[ArgTblOfs + i]]);
+		}
+		}
+		if (i < InstArgTbl[ArgTblOfs])
+			len += sprintf(&Text[len], ",");
+	}
+
+	return InstSize;
 }