X-Git-Url: http://gitweb.hugovil.com/?a=blobdiff_plain;f=src%2Fcpu8051.c;h=55e761a75e4a4c431b23d406df6c9ff4218bb22e;hb=8d9b71ab3848729da1cf90a38a599be0b08cbb5c;hp=a44cd7fe6131f7d23a985dd26f4663b8adecee65;hpb=593009d28f70be7e5deebc7a44c16e85c2574422;p=emu8051.git

diff --git a/src/cpu8051.c b/src/cpu8051.c
index a44cd7f..55e761a 100644
--- a/src/cpu8051.c
+++ b/src/cpu8051.c
@@ -28,6 +28,7 @@
 #include "reg8051.h"
 #include "cpu8051.h"
 #include "memory.h"
+#include "psw.h"
 #include "disasm.h"
 #include "instructions_8051.h"
 
@@ -118,6 +119,8 @@ cpu8051_Reset(void)
 	memory_sfr_write8(_P1_, 0xFF);
 	memory_sfr_write8(_P2_, 0xFF);
 	memory_sfr_write8(_P3_, 0xFF);
+
+	/* The default value of SP (after system reset) is 07 */
 	memory_sfr_write8(_SP_, 0x07);
 }
 
@@ -209,12 +212,7 @@ cpu8051_ReadB(uint8_t bit_address)
 static void
 cpu8051_process_interrupt(int pc, int pri)
 {
-	unsigned char SP;
-
-	SP = cpu8051_ReadD(_SP_);
-	cpu8051_WriteI(++SP, (cpu8051.pc & 0xFF));
-	cpu8051_WriteI(++SP, (cpu8051.pc >> 8));
-	cpu8051_WriteD(_SP_, SP);
+	stack_push16(pc);
 	cpu8051.pc = 0x0B;
 	cpu8051.active_priority = pri;
 }
@@ -377,6 +375,12 @@ cpu8051_Exec(void)
 	cpu8051.pc++;
 	insttiming = (*opcode_table[opcode])(); /* Function callback. */
 
+	/*
+	 * Parity bit (p): is automatically set or cleared in each machine
+	 * cycle to establish even parity in the accumulator.
+	 */
+	psw_compute_parity_bit();
+
 	for (i = 0; i < insttiming; i++) {
 		cpu8051_CheckInterrupts();
 		cpu8051_DoTimers();