X-Git-Url: http://gitweb.hugovil.com/?a=blobdiff_plain;f=src%2Fmemory.c;h=c5b2acf51c7384776af89fe6b60ad346e27bebcd;hb=8d9b71ab3848729da1cf90a38a599be0b08cbb5c;hp=057af5660fb0f10f4321c3bd830a40c289406eab;hpb=3615ed71ecaa97d539debdf803fa5f3ea21e4a1e;p=emu8051.git

diff --git a/src/memory.c b/src/memory.c
index 057af56..c5b2acf 100644
--- a/src/memory.c
+++ b/src/memory.c
@@ -70,6 +70,8 @@ memory_init(void)
 			log_err("%s", strerror(errno));
 			exit(1);
 		}
+
+		memset(m->buf, 0x00, m->size);
 	}
 }
 
@@ -131,6 +133,70 @@ 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;
+}
+
+/* Read a 16-bit address from PGM memory, starting at <base> offset */
+uint16_t
+pgm_read_addr16(uint16_t base)
+{
+	uint16_t addr;
+
+	addr = memory_read8(PGM_MEM_ID, base) << 8; /* MSB */
+	addr |= memory_read8(PGM_MEM_ID, base + 1); /* LSB */
+
+	return addr;
+}
+
 /* Dump memory */
 void
 DumpMem(char *Address, char *Asize, int memory_id)