From: Hugo Villeneuve <hugo@hugovil.com>
Date: Sat, 16 Nov 2013 19:22:20 +0000 (-0500)
Subject: Add stack push/pop functions
X-Git-Tag: v2.0.0~91
X-Git-Url: http://gitweb.hugovil.com/?a=commitdiff_plain;h=21fb2cf2a3c16d19ec65a3afacdcb15a90a38340;p=emu8051.git

Add stack push/pop functions
---

diff --git a/src/cpu8051.c b/src/cpu8051.c
index 213f61b..58a0e79 100644
--- a/src/cpu8051.c
+++ b/src/cpu8051.c
@@ -211,12 +211,7 @@ 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;
 }
diff --git a/src/memory.c b/src/memory.c
index 057af56..ac8bca5 100644
--- a/src/memory.c
+++ b/src/memory.c
@@ -131,6 +131,58 @@ memory_sfr_read_dptr(void)
 		memory_read8(INT_MEM_ID, _DPTRLOW_);
 }
 
+void
+stack_push8(uint8_t value)
+{
+	uint8_t sp;
+
+	sp = memory_read8(INT_MEM_ID, _SP_);
+
+	memory_write8(INT_MEM_ID, ++sp, value);
+	memory_write8(INT_MEM_ID, _SP_, sp); /* Save new stack pointer */
+}
+
+void
+stack_push16(uint16_t value)
+{
+	uint8_t sp;
+
+	sp = memory_read8(INT_MEM_ID, _SP_);
+
+	memory_write8(INT_MEM_ID, ++sp, (uint8_t) value); /* Write LSB */
+	memory_write8(INT_MEM_ID, ++sp, value >> 8);      /* Write MSB */
+	memory_write8(INT_MEM_ID, _SP_, sp); /* Save new stack pointer */
+}
+
+uint8_t
+stack_pop8(void)
+{
+	uint8_t sp;
+	uint8_t value;
+
+	sp = memory_read8(INT_MEM_ID, _SP_);
+
+	value = memory_read8(INT_MEM_ID, sp--);
+	memory_write8(INT_MEM_ID, _SP_, sp); /* Save new stack pointer */
+
+	return value;
+}
+
+uint16_t
+stack_pop16(void)
+{
+	uint8_t sp;
+	uint16_t value;
+
+	sp = memory_read8(INT_MEM_ID, _SP_);
+
+	value = memory_read8(INT_MEM_ID, sp--) << 8; /* Read MSB */
+	value |= memory_read8(INT_MEM_ID, sp--);     /* Read LSB */
+	memory_write8(INT_MEM_ID, _SP_, sp); /* Save new stack pointer */
+
+	return value;
+}
+
 /* Dump memory */
 void
 DumpMem(char *Address, char *Asize, int memory_id)
diff --git a/src/memory.h b/src/memory.h
index e8ac7ee..c8761e9 100644
--- a/src/memory.h
+++ b/src/memory.h
@@ -67,6 +67,18 @@ memory_sfr_read8(unsigned long address);
 u_int16_t
 memory_sfr_read_dptr(void);
 
+void
+stack_push8(uint8_t value);
+
+void
+stack_push16(uint16_t value);
+
+uint8_t
+stack_pop8(void);
+
+uint16_t
+stack_pop16(void);
+
 void
 DumpMem(char *Address, char *Asize, int memory_id);
 
diff --git a/src/opcode2c.pl b/src/opcode2c.pl
index a72c8f7..2c8a149 100755
--- a/src/opcode2c.pl
+++ b/src/opcode2c.pl
@@ -417,18 +417,12 @@ for ($i=0 ; $i< 256; $i++) {
 
 	# ACALL
 	if ($insttype[$i] == 6) {
-	    print INST_IMP "unsigned char SP = cpu8051_ReadD( _SP_ );\n";
-	    print INST_IMP "cpu8051_WriteI( ++SP, ( cpu8051.pc & 0x00FF ) );\n";
-	    print INST_IMP "cpu8051_WriteI( ++SP, ( cpu8051.pc >> 8 ) );\n";
-	    print INST_IMP "cpu8051_WriteD( _SP_, SP );\n";
+	    print INST_IMP "stack_push16(cpu8051.pc);\n";
 	}
 
 	# LCALL
 	if ($insttype[$i] == 7) {
-	    print INST_IMP "unsigned char SP = cpu8051_ReadD( _SP_ );\n";
-	    print INST_IMP "cpu8051_WriteI( ++SP, ( cpu8051.pc & 0x00FF ) );\n";
-	    print INST_IMP "cpu8051_WriteI( ++SP, ( cpu8051.pc >> 8 ) );\n";
-	    print INST_IMP "cpu8051_WriteD( _SP_, SP );\n";
+	    print INST_IMP "stack_push16(cpu8051.pc);\n";
 	}
 
 	# RRC
@@ -450,10 +444,7 @@ for ($i=0 ; $i< 256; $i++) {
 
 	# RET
 	if ($insttype[$i] == 11) {
-	    print INST_IMP "unsigned char SP = cpu8051_ReadD( _SP_ );\n";
-	    print INST_IMP "cpu8051.pc = ( cpu8051_ReadI( SP-- ) << 8 );\n";
-	    print INST_IMP "cpu8051.pc += cpu8051_ReadI ( SP-- );\n";
-	    print INST_IMP "cpu8051_WriteD( _SP_, SP );\n";
+            print INST_IMP "cpu8051.pc = stack_pop16();\n";
 	}
 
 	# RL
@@ -480,10 +471,7 @@ for ($i=0 ; $i< 256; $i++) {
 	# RETI
 	if ($insttype[$i] == 15) {
 	    print INST_IMP "cpu8051.active_priority = -1;\n";
-	    print INST_IMP "unsigned char SP = cpu8051_ReadD( _SP_ );\n";
-	    print INST_IMP "cpu8051.pc = ( cpu8051_ReadI( SP-- ) << 8 );\n";
-	    print INST_IMP "cpu8051.pc += cpu8051_ReadI( SP-- );\n";
-	    print INST_IMP "cpu8051_WriteD( _SP_, SP );\n";
+            print INST_IMP "cpu8051.pc = stack_pop16();\n";
 	}
 
 	# RLC
@@ -605,9 +593,7 @@ for ($i=0 ; $i< 256; $i++) {
 
 	# PUSH
 	if ($insttype[$i] == 35) {
-	    print INST_IMP "unsigned char SP = cpu8051_ReadD( _SP_ );\n";
-	    print INST_IMP "cpu8051_WriteI( ++SP, destination );\n";
-	    print INST_IMP "cpu8051_WriteD( _SP_, SP );\n";
+	    print INST_IMP "stack_push8(destination);\n";
 	}
 
 	# CLR
@@ -629,9 +615,7 @@ for ($i=0 ; $i< 256; $i++) {
 
 	# POP
 	if ($insttype[$i] == 39) {
-	    print INST_IMP "unsigned char SP = cpu8051_ReadD( _SP_ );\n";
-	    print INST_IMP "destination = cpu8051_ReadI( SP-- );\n";
-	    print INST_IMP "cpu8051_WriteD( _SP_, SP );\n";
+            print INST_IMP "destination = stack_pop8();\n";
 	}
 
 	# SETB