X-Git-Url: http://git.joshuawise.com/fpgaboy.git/blobdiff_plain/3ad960bdb71efcbb1dfd436163085da0d70eb699..df770340caf8ecd26a55179484edb507082bd5c6:/insn_call-callcc.v

diff --git a/insn_call-callcc.v b/insn_call-callcc.v
new file mode 100644
index 0000000..bb7c14a
--- /dev/null
+++ b/insn_call-callcc.v
@@ -0,0 +1,57 @@
+`ifdef EXECUTE
+	`INSN_CALL,`INSN_CALLCC: begin
+		case (cycle)
+		0:	begin
+				`EXEC_INC_PC;
+				`EXEC_NEXTADDR_PCINC;
+				rd <= 1;
+			end
+		1:	begin
+				`EXEC_INC_PC;
+				`EXEC_NEXTADDR_PCINC;
+				rd <= 1;
+			end
+		2:	begin
+				`EXEC_INC_PC;
+				if (!opcode[0])	// i.e., is callcc
+					/* We need to check the condition code to bail out. */
+					case (opcode[4:3])
+					`INSN_cc_NZ:	if (registers[`REG_F][7]) begin `EXEC_NEWCYCLE; end
+					`INSN_cc_Z:	if (~registers[`REG_F][7]) begin `EXEC_NEWCYCLE; end
+					`INSN_cc_NC:	if (registers[`REG_F][4]) begin `EXEC_NEWCYCLE; end
+					`INSN_cc_C:	if (~registers[`REG_F][4]) begin `EXEC_NEWCYCLE; end
+					endcase
+			end
+		3:	begin
+				address <= {registers[`REG_SPH],registers[`REG_SPL]} - 1;
+				wdata <= registers[`REG_PCH];
+				wr <= 1;
+			end
+		4:	begin
+				address <= {registers[`REG_SPH],registers[`REG_SPL]} - 2;
+				wdata <= registers[`REG_PCL];
+				wr <= 1;
+			end
+		5:	begin
+				`EXEC_NEWCYCLE;	/* do NOT increment the PC */
+			end
+		endcase
+	end
+`endif
+
+`ifdef WRITEBACK
+	`INSN_CALL,`INSN_CALLCC: begin
+		case (cycle)
+		0:	begin /* type F */ end
+		1:	tmp <= rdata;	// tmp contains newpcl
+		2:	tmp2 <= rdata;	// tmp2 contains newpch
+		3:	begin /* type F */ end
+		4:	registers[`REG_PCH] <= tmp2;
+		5: begin
+				{registers[`REG_SPH],registers[`REG_SPL]} <=
+					{registers[`REG_SPH],registers[`REG_SPL]} - 2;
+				registers[`REG_PCL] <= tmp;
+			end
+		endcase
+	end
+`endif