diff options
| -rw-r--r-- | zpu/ChangeLog | 3 | ||||
| -rw-r--r-- | zpu/hdl/zpu4/core/zpu_core.vhd | 32 |
2 files changed, 34 insertions, 1 deletions
diff --git a/zpu/ChangeLog b/zpu/ChangeLog index e190a9f..2ed7369 100644 --- a/zpu/ChangeLog +++ b/zpu/ChangeLog @@ -1,3 +1,6 @@ +2008-11-12 Álvaro Lopes <alvieboy@alvie.com>
+ * zpu/hdl/zpu4/core/zpu_core.vhd: Basic interrupt implementation
+ for zpu4 core.
2008-09-16 Salvador Eduardo Tropea <salvador@inti.gob.ar>
* zpu/hdl/zealot: added small ZPU core, testbenches and FPGA implementation
2008-09-11 Salvador Eduardo Tropea <salvador@inti.gob.ar>
diff --git a/zpu/hdl/zpu4/core/zpu_core.vhd b/zpu/hdl/zpu4/core/zpu_core.vhd index 012fe1b..69da686 100644 --- a/zpu/hdl/zpu4/core/zpu_core.vhd +++ b/zpu/hdl/zpu4/core/zpu_core.vhd @@ -1,6 +1,7 @@ -- ZPU
--
-- Copyright 2004-2008 oharboe - Øyvind Harboe - oyvind.harboe@zylin.com
+-- Copyright 2008 alvieboy - Álvaro Lopes - alvieboy@alvie.com
--
-- The FreeBSD license
--
@@ -145,7 +146,8 @@ State_Mult5, State_Mult4,
State_BinaryOpResult2,
State_BinaryOpResult,
-State_Idle
+State_Idle,
+State_Interrupt
);
@@ -171,6 +173,8 @@ signal mem_addr : std_logic_vector(maxAddrBitIncIO downto minAddrBit); signal mem_delayAddr : std_logic_vector(maxAddrBitIncIO downto minAddrBit);
signal mem_delayReadEnable : std_logic;
+signal inInterrupt: std_logic;
+
signal decodeWord : std_logic_vector(wordSize-1 downto 0);
@@ -244,6 +248,7 @@ begin pc <= (others => '0');
idim_flag <= '0';
begin_inst <= '0';
+ inInterrupt <= '0';
mem_writeEnable <= '0';
mem_readEnable <= '0';
multA <= (others => '0');
@@ -288,6 +293,10 @@ begin trace_topOfStackB <= std_logic_vector(stackB);
begin_inst <= '0';
+ if (interrupt='0') then
+ -- Interrupt ended, we can serve ISR again
+ inInterrupt <= '0';
+ end if;
case state is
when State_Idle =>
@@ -319,6 +328,27 @@ begin if in_mem_busy='0' then
decodeWord <= mem_read;
state <= State_Decode2;
+ -- Do not recurse into ISR while interrupt line is active
+ if interrupt='1' and inInterrupt='0' and idim_flag='0' then
+ -- We got an interrupt, execute interrupt instead of next instruction
+ inInterrupt <= '1';
+ sp <= decSp;
+ mem_writeEnable <= '1';
+ mem_addr <= std_logic_vector(incSp);
+ mem_write <= std_logic_vector(stackB);
+ stackA <= (others => DontCareValue);
+ stackA(maxAddrBitIncIO downto 0) <= pc;
+ stackB <= stackA;
+ pc <= to_unsigned(32, maxAddrBitIncIO+1);
+ state <= State_Interrupt;
+ end if;
+ end if;
+ when State_Interrupt =>
+ if in_mem_busy='0' then
+ mem_addr <= std_logic_vector(pc(maxAddrBitIncIO downto minAddrBit));
+ mem_readEnable <= '1';
+ state <= State_Decode;
+ report "ZPU jumped to interrupt!" severity note;
end if;
when State_Decode2 =>
-- decode 4 instructions in parallel
|
