From c64dee965fa00a4b7e3c3705da5e226ea56082ed Mon Sep 17 00:00:00 2001
From: Alejandro Soto <alejandro@34project.org>
Date: Wed, 16 Nov 2022 19:55:25 -0600
Subject: Implement JTAG-UART tx emulation

---
 tb/jtag_uart.cpp | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)
 create mode 100644 tb/jtag_uart.cpp

(limited to 'tb/jtag_uart.cpp')

diff --git a/tb/jtag_uart.cpp b/tb/jtag_uart.cpp
new file mode 100644
index 0000000..78d438e
--- /dev/null
+++ b/tb/jtag_uart.cpp
@@ -0,0 +1,55 @@
+#include "avalon.hpp"
+#include "jtag_uart.hpp"
+
+namespace taller::avalon
+{
+	jtag_uart::jtag_uart(std::uint32_t base) noexcept
+	: slave(base, 8, 4)
+	{}
+
+	bool jtag_uart::read(std::uint32_t addr, std::uint32_t &data) noexcept
+	{
+		switch(addr)
+		{
+			case 0:
+				data = 0; //TODO
+				break;
+
+			case 1:
+				data =
+					  static_cast<std::uint32_t>(ctrl_re) << 0
+					| static_cast<std::uint32_t>(ctrl_we) << 1
+					//TODO: varios bits
+					| static_cast<std::uint32_t>(ctrl_ac) << 10
+					//TODO: disponibilidad de tx fifo
+					| static_cast<std::uint32_t>(255) << 10;
+
+				break;
+		}
+
+		return true;
+	}
+
+	bool jtag_uart::write(std::uint32_t addr, std::uint32_t data, unsigned byte_enable) noexcept
+	{
+		switch(addr)
+		{
+			case 0:
+				putchar(data & 0xff);
+				ctrl_ac = 1;
+				break;
+
+			case 1:
+				ctrl_re = !!(data & (1 << 0));
+				ctrl_we = !!(data & (1 << 1));
+				if(!!(data & (1 << 10)))
+				{
+					ctrl_ac = 0;
+				}
+
+				break;
+		}
+
+		return true;
+	}
+}
-- 
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