backlog of changes from the uconsole

3mu/Intel4004.c

@@ -15,6 +15,7 @@
  * nybbles     4--|4--|4--|4--|4--|4--|
  * bits        111111111111111111111111 */
 
+#include <complex.h>
 #if __STDC_VERSION__ >= 199901L
 /* C99 type definitions */
 #	include <stdint.h>
@@ -42,6 +43,7 @@ struct Intel4004_State {
 	Nybble acc;     /* Accumulator */
 	Nybble reg[16]; /* R0 through RF */
 	Word pc[4];     /* PC0 through PC3 */
+	Word *cc;       /* Current PC */
 	Byte *rom;
 	Byte *ram;
 };
@@ -117,11 +119,38 @@ enum Intel4004_Instruction {
 /* INVALID                             0xFF     0b 1111 1111 */
 };
 
+#define INTEL4004_THIS_OP (state->rom[*state->cc])
+#define INTEL4004_NEXT_OP (state->rom[*state->cc + 1])
+#define INTEL4004_INC_OP do{ ++*state->cc; }while(0)
+#define INTEL4004_INC2_OP do{ *state->cc += 2; }while(0)
+
+/* <http://e4004.szyc.org/>-style naming */
+#define INTEL4004_PL  (*state->cc & 0x00F)
+#define INTEL4004_PM ((*state->cc & 0x0F0) >> 4)
+#define INTEL4004_PH ((*state->cc & 0xF00) >> 8)
+
+/* Also see the Intel MCS-4 Assembly Language Programming Manual (1973). */
+
+/* From the datasheet. */
+void Intel4004_RESET(struct Intel4004_State *state){
+	Nybble i;
+
+	state->carry = 0;
+	state->test = 0;
+	state->acc = 0;
+	for(i = 0; i <= (sizeof state->reg) / (sizeof *state->reg); ++i)
+		state->reg[i] = 0;
+	for(i = 0; i <= (sizeof state->pc) / (sizeof *state->pc); ++i)
+		state->pc[i] = 0;
+	state->cc = &state->pc[0];
+
+	return;
+}
+
 /* Does nothing. */
 void Intel4004_NOP(struct Intel4004_State *state){ /* 0b 0000 0000 */
 
-	++*state->pc;
-
+	INTEL4004_INC_OP;
 	return;
 }
 
@@ -141,16 +170,16 @@ void Intel4004_NOP(struct Intel4004_State *state){ /* 0b 0000 0000 */
  * If *state->pc & 0x08, a one test flag satisfies the condition. */
 void Intel4004_JCN(struct Intel4004_State *state){ /* 0b 0001 CCCC */
 
-	*state->pc =
-			!INTEL4004_JCN_COND_ISINVERT(state->rom[*state->pc])
-			&& (   (INTEL4004_JCN_COND_ISACCZERO(state->rom[*state->pc])
+	*state->cc =
+			!INTEL4004_JCN_COND_ISINVERT(INTEL4004_THIS_OP)
+			&& (   (INTEL4004_JCN_COND_ISACCZERO(INTEL4004_THIS_OP)
 					&& state->acc == 0)
-				|| (INTEL4004_JCN_COND_ISCARRYON(state->rom[*state->pc])
+				|| (INTEL4004_JCN_COND_ISCARRYON(INTEL4004_THIS_OP)
 				    && state->carry == 1)
-				|| (INTEL4004_JCN_COND_ISTESTON(state->rom[*state->pc])
+				|| (INTEL4004_JCN_COND_ISTESTON(INTEL4004_THIS_OP)
 				    && state->test == 1))
-		? state->rom[*state->pc + 1]
-		: *state->pc + 2;
+		? state->rom[*state->cc + 1]
+		: *state->cc + 2;
 
 	return;
 }
@@ -166,14 +195,13 @@ void Intel4004_JCN(struct Intel4004_State *state){ /* 0b 0001 CCCC */
 /* Fetches an immediate byte from ROM. */
 void Intel4004_FIM(struct Intel4004_State *state){ /* 0b 0010 RRR0 */
 
-	state->reg[INTEL4004_REGPAIR(state->rom[*state->pc])]
-		= HIGH_NYBBLE(state->rom[*state->pc + 1]);
+	state->reg[INTEL4004_REGPAIR(INTEL4004_THIS_OP)]
+		= HIGH_NYBBLE(INTEL4004_NEXT_OP);
 
-	state->reg[INTEL4004_REGPAIR(state->rom[*state->pc]) + 1]
-		= LOW_NYBBLE(state->rom[*state->pc + 1]);
-
-	*state->pc += 2;
+	state->reg[INTEL4004_REGPAIR(INTEL4004_THIS_OP) + 1]
+		= LOW_NYBBLE(INTEL4004_NEXT_OP);
 
+	INTEL4004_INC2_OP;
 	return;
 }
 
@@ -182,3 +210,37 @@ void Intel4004_SRC(struct Intel4004_State *state){ /* 0b 0010 RRR1 */
 
 void Intel4004_FIN(struct Intel4004_State *state){ /* 0b 0011 RRR0 */
 }
+
+/* Loads the immediate value in the low nybble of the opcode into the
+ * accumulator. */
+void Intel4004_LDM(struct Intel4004_State *state){ /* 0b 1101 DDDD */
+
+	state->acc = LOW_NYBBLE(INTEL4004_THIS_OP);
+
+	INTEL4004_INC_OP;
+	return;
+}
+
+void Intel4004_BBL(struct Intel4004_State *state){ /* 0b 1100 DDDD */
+/* <http://e4004.szyc.org/> lists 0b 1100 RRRR, most likely as a typo. I found
+ * 0b 1100 DDDD on the Intel 4004 datasheet. */
+
+	return Intel4004_LDM(state);
+}
+
+/* Clears the carry bit. */
+void Intel4004_CLC(struct Intel4004_State *state){ /* 0b 1111 0001 */
+
+	state->carry = 0;
+
+	INTEL4004_INC_OP;
+	return;
+}
+
+/* Clears both the accumulator and the carry bit. */
+void Intel4004_CLB(struct Intel4004_State *state){ /* 0b 1111 0000 */
+
+	state->acc = 0;
+
+	return Intel4004_CLC(state);
+}