new FP multiply unit, with thanks to Joao Pampanini

cMIPS/bin/build.sh

@@ -66,7 +66,7 @@ simulator=tb_cmips
 
 pkg="packageWires.vhd packageMemory.vhd packageExcp.vhd"
 
-src="altera.vhd macnica.vhd aux.vhd memory.vhd cache.vhd instrcache.vhd ram.vhd rom.vhd units.vhd io.vhd uart.vhd pipestages.vhd exception.vhd core.vhd tb_cMIPS.vhd"
+src="altera.vhd macnica.vhd aux.vhd memory.vhd cache.vhd instrcache.vhd ram.vhd rom.vhd units.vhd io.vhd uart.vhd fpu.vhd pipestages.vhd exception.vhd core.vhd tb_cMIPS.vhd"
 
 # build simulator
 #ghdl --clean

cMIPS/docs/installCrosscompiler

-#!/bin/bash
+###
+### this file in NOT a shell script,
+### yet it was written to make it easy for cutting-n-pasting with the pointer
+###
 
 # to compile GCC, these three libraries may have to be fetched:
 
@@ -12,11 +15,13 @@ wget ftp://ftp.gmplib.org/pub/gmp/gmp-6.0.0.tar.bz2
 # directory names to mpfr mpc gmp (removing the version suffixes);
 # these libraries are then compiled along with GCC
 
-# OTOH, if you are lucky, the libraries installed by aptitude will do...
+# OTOH, if you are very lucky, the libraries installed by aptitude will do...
 
 # fetch all the auxiliary programs -- this assumes a Debian installation
 aptitude install make flex bison libgmp-dev libmpfr-dev libmpc-dev g++
 unset ls
+
+# make sure the installed files are read-exec by all
 umask 022
 
 # check the latest version of GCC in http://ftp.gnu.org/gnu/gcc/
@@ -38,17 +43,22 @@ tar -xvjf ${BINUTILS}.tar.bz2
 cd ${BINUTILS}
 ./configure --target=$TARGET --prefix=$PREFIX --disable-nls
 make
+
 # do the next one as root?  su ; umask 022 ; make install ; exit
+
 make install
 cd ..
 
 tar -xvzf ${COMPILER}.tar.gz
 cd ${COMPILER}
+
 # you may want/need to expand the libraries' tarballs at this point
+
 export PATH=$PATH:$PREFIX/bin
 ./configure --target=$TARGET --prefix=$PREFIX --disable-nls \
      --enable-languages=c,c++ --without-headers
 make all-gcc
+
 # do the next one as root?  su ; umask 022 ; make install-gcc ; exit
 make install-gcc
 cd ..
@@ -69,8 +79,13 @@ export MANPATH=${MANPATH}:${PREFIX}/man
 #    https://sourceforge.net/p/ghdl-updates/wiki/Debian%20Instructions/
 #  and pick the appropriate version for your computer (32 or 64 bit).
 #
-# When doing  dpkg -i ghdl*.deb  it will complain about versions.
-#  What I have done is use the following DANGEROUS and RISKY command:
-#  dpkg --ignore-depends=ghdl*.deb  -i ghdl*.deb
-#  this forces dpkg to ignore the dependencies for GHDL and install it
-#  with whatever version your machine has for gnat.  The risk is yours.
+# You also need to fetch gnat and libgnat from somewhere; I find it easier
+#  to download the .deb files onto the same directory as ghdl*.deb
+#
+# When doing  dpkg -i ghdl*.deb  it will whine and complain about versions.
+#  What I have done is to use the following DANGEROUS and RISKY command:
+#
+#  dpkg --ignore-depends=ghdl*.deb --ignore-depends=libgnat-4.6 -i ghdl*.deb
+#
+#  it forces dpkg to ignore the dependencies for GHDL and install it
+#  with whatever version your machine has for gnat/libgnat.  Caveat emptor.

cMIPS/tests/FPU_m.c

+#include "cMIPS.h"
+
+//  ALL NaN cases :  set  i < 11 stop case
+//  int A[] = {(int)0x7fffffff,(int)0x7fffffff,(int)0x7fffffff,(int)0x7fffffff,(int)0x7fffffff,(int)0x7fffffff,(int)0x7fffffff,(int)0x7f800000,(int)0x7f800000,(int)0xff800000,(int)0xff800000};
+//  int B[] = {(int)0x7fffffff,(int)0x7f800000,(int)0xff800000,(int)0x00000000,(int)0x80000000,(int)0x1c038000,(int)0x9c038000,(int)0x00000000,(int)0x80000000,(int)0x00000000,(int)0x80000000};
+//  int C[] = {(int)0x7fffffff,(int)0x7fffffff,(int)0x7fffffff,(int)0x7fffffff,(int)0x7fffffff,(int)0x7fffffff,(int)0x7fffffff,(int)0x7fffffff,(int)0x7fffffff,(int)0x7fffffff,(int)0x7fffffff};
+//  ALL inf cases :  set  i < 12 stop case
+//  int A[] = {(int)0x7f800000,(int)0xff800000,(int)0x7f800000,(int)0xff800000,(int)0x7f000000,(int)0xff000000,(int)0xff800000,(int)0xff800000,(int)0x7f800000,(int)0xff800000,(int)0x7f000000,(int)0xff000000};
+//  int B[] = {(int)0x7f800000,(int)0xff800000,(int)0x1c038000,(int)0x9c038000,(int)0x7f000000,(int)0xff000000,(int)0x7f800000,(int)0x1c038000,(int)0x9c038000,(int)0x1c038000,(int)0xff000000,(int)0x7f000000};
+//  int C[] = {(int)0x7f800000,(int)0x7f800000,(int)0x7f800000,(int)0x7f800000,(int)0x7f800000,(int)0x7f800000,(int)0xff800000,(int)0xff800000,(int)0xff800000,(int)0xff800000,(int)0xff800000,(int)0xff800000};
+//  ALL 0 cases :  set  i < 12 stop case
+//  int A[] = {(int)0x00000000,(int)0x80000000,(int)0x00000000,(int)0x80000000,(int)0x00800000,(int)0x80800000,(int)0x00000000,(int)0x00000000,(int)0x80000000,(int)0x80000000,(int)0x00800000,(int)0x80800000};
+//  int B[] = {(int)0x00000000,(int)0x80000000,(int)0x1c038000,(int)0x9c038000,(int)0x00800000,(int)0x80800000,(int)0x9c038000,(int)0x80000000,(int)0x00000000,(int)0x1c038000,(int)0x80800000,(int)0x00800000};
+//  int C[] = {(int)0x00000000,(int)0x00000000,(int)0x00000000,(int)0x00000000,(int)0x00000000,(int)0x00000000,(int)0x80800000,(int)0x80800000,(int)0x80800000,(int)0x80800000,(int)0x80800000,(int)0x80800000};
+//  denorm cases :  set  i < 3 stop case
+//  int A[] = {(int)0x3c000000,(int)0x3c000000,(int)0x3f800000};
+//  int B[] = {(int)0x03800000,(int)0x03000000,(int)0x00200000};
+//  int C[] = {(int)0x00400000,(int)0x00200000,(int)0x00200000};
+
+
+  int A[] = {
+    // normal numbers
+    (int)0x9c038000,(int)0x9c038000,(int)0x9c038000,(int)0x9c038000,
+    // denormalized 
+    (int)0x3c000000,(int)0x3c000000,(int)0x3f800000,
+    // all 0 cases :  set  i < 12 stop case
+    (int)0x00000000,(int)0x80000000,(int)0x00000000,(int)0x80000000,
+    (int)0x00800000,(int)0x80800000,(int)0x00000000,(int)0x00000000,
+    (int)0x80000000,(int)0x80000000,(int)0x00800000,(int)0x80800000,
+    // all inf cases :  set  i < 12 stop case
+    (int)0x7f800000,(int)0xff800000,(int)0x7f800000,(int)0xff800000,
+    (int)0x7f000000,(int)0xff000000,(int)0xff800000,(int)0xff800000,
+    (int)0x7f800000,(int)0xff800000,(int)0x7f000000,(int)0xff000000,
+    // all NaN cases :  set  i < 11 stop case
+    (int)0x7fffffff,(int)0x7fffffff,(int)0x7fffffff,(int)0x7fffffff,
+    (int)0x7fffffff,(int)0x7fffffff,(int)0x7fffffff,(int)0x7f800000,
+    (int)0x7f800000,(int)0xff800000,(int)0xff800000
+  };
+
+  int B[] = {
+    // normal numbers
+    (int)0x3f800000,(int)0x3f800000,(int)0x3f800000,(int)0x3f800000,
+    // denormalized
+    (int)0x03800000,(int)0x03000000,(int)0x00200000,
+    // all 0 cases
+    (int)0x00000000,(int)0x80000000,(int)0x1c038000,(int)0x9c038000,
+    (int)0x00800000,(int)0x80800000,(int)0x9c038000,(int)0x80000000,
+    (int)0x00000000,(int)0x1c038000,(int)0x80800000,(int)0x00800000,
+    // all inf cases
+    (int)0x7f800000,(int)0xff800000,(int)0x1c038000,(int)0x9c038000,
+    (int)0x7f000000,(int)0xff000000,(int)0x7f800000,(int)0x1c038000,
+    (int)0x9c038000,(int)0x1c038000,(int)0xff000000,(int)0x7f000000,
+    // all NaN cases
+    (int)0x7fffffff,(int)0x7f800000,(int)0xff800000,(int)0x00000000,
+    (int)0x80000000,(int)0x1c038000,(int)0x9c038000,(int)0x00000000,
+    (int)0x80000000,(int)0x00000000,(int)0x80000000
+  };
+
+  int C[] = {
+    // normal numbers
+    (int)0x9c038000,(int)0x9c038000,(int)0x9c038000,(int)0x9c038000,
+    // denorm
+    (int)0x00400000,(int)0x00200000,(int)0x00200000,
+    // all 0 cases
+    (int)0x00000000,(int)0x00000000,(int)0x00000000,(int)0x00000000,
+    (int)0x00000000,(int)0x00000000,(int)0x80800000,(int)0x80800000,
+    (int)0x80800000,(int)0x80800000,(int)0x80800000,(int)0x80800000,
+    // all inf cases
+    (int)0x7f800000,(int)0x7f800000,(int)0x7f800000,(int)0x7f800000,
+    (int)0x7f800000,(int)0x7f800000,(int)0xff800000,(int)0xff800000,
+    (int)0xff800000,(int)0xff800000,(int)0xff800000,(int)0xff800000,
+    // all NaN cases
+    (int)0x7fffffff,(int)0x7fffffff,(int)0x7fffffff,(int)0x7fffffff,
+    (int)0x7fffffff,(int)0x7fffffff,(int)0x7fffffff,(int)0x7fffffff,
+    (int)0x7fffffff,(int)0x7fffffff,(int)0x7fffffff
+};
+
+
+void main(void) {
+  int i,j, acc;
+  volatile int *fpu,res;        // address of fpu
+
+  fpu = (int *)IO_FPU_ADDR;        // 0x0f0000c0; // MUL
+  // fpu = (int *)IO_FPU_ADDR + 4; // 0x0f0000c8; // ADD
+  // fpu = (int *)IO_FPU_ADDR + 8; // 0x0f0000cc; // DIV
+
+  acc = 0;
+  for (i = 0; i < 4; i++) { // ordinary cases
+      *fpu = A[i];
+      *(fpu+1) = B[i];
+      asm("nop");
+      res = *fpu;
+      if (res != C[i])
+        acc = 1;
+  }
+  if (acc == 0) {
+    to_stdout('o'); to_stdout('r'); to_stdout('d'); to_stdout('\n');
+  } else {
+    to_stdout('E'); to_stdout('R'); to_stdout('R'); to_stdout('\n');
+  }
+
+  acc = 0;
+  for ( ; i < 4+3; i++) { // denormalized
+      *fpu = A[i];
+      *(fpu+1) = B[i];
+      asm("nop");
+      res = *fpu;
+      if (res != C[i])
+        acc = 1;
+  }
+  if (acc == 0) {
+    to_stdout('d'); to_stdout('e'); to_stdout('n'); to_stdout('\n');
+  } else {
+    to_stdout('E'); to_stdout('R'); to_stdout('R'); to_stdout('\n');
+  }
+
+  acc = 0;
+  for ( ; i < 7+12; i++) { // zeroes
+      *fpu = A[i];
+      *(fpu+1) = B[i];
+      asm("nop");
+      res = *fpu;
+      if (res != C[i])
+        acc = 1;
+  }
+  if (acc == 0) {
+    to_stdout('z'); to_stdout('e'); to_stdout('r'); to_stdout('\n');
+  } else {
+    to_stdout('E'); to_stdout('R'); to_stdout('R'); to_stdout('\n');
+  }
+
+  acc = 0;
+  for ( ; i < 19+12; i++) { // infinites
+      *fpu = A[i];
+      *(fpu+1) = B[i];
+      asm("nop");
+      res = *fpu;
+      if (res != C[i])
+        acc = 1;
+  }
+  if (acc == 0) {
+    to_stdout('i'); to_stdout('n'); to_stdout('f'); to_stdout('\n');
+  } else {
+    to_stdout('E'); to_stdout('R'); to_stdout('R'); to_stdout('\n');
+  }
+
+  acc = 0;
+  for ( ; i < 21+11; i++) { // NaNs
+      *fpu = A[i];
+      *(fpu+1) = B[i];
+      asm("nop");
+      res = *fpu;
+      if (res != C[i])
+        acc = 1;
+  }
+  if (acc == 0) {
+    to_stdout('N'); to_stdout('a'); to_stdout('N'); to_stdout('\n');
+  } else {
+    to_stdout('E'); to_stdout('R'); to_stdout('R'); to_stdout('\n');
+  }
+
+}

cMIPS/tests/mmu_tlbwi.s

@@ -231,14 +231,6 @@ read3:	tlbr 			# read TLB at index = 3
 	.set TAG_MASK, 0xfffff000 	# 4Kbyte pages
 	.set TAG_G,     0x00000000	# mark pages as global
 
-#	.set MMU_ini_tag_RAM6, ((x_RAM_PPN_6 & TAG_MASK) | TAG_G)
-	
-#	.set x_RAM_PPN_6, (x_DATA_BASE_ADDR + 6*PAGE_SZ)
-#	.set MMU_ini_dat_RAM6, (((x_RAM_PPN_6 >>12) <<6) | 0b000111) # d,v,g=1
-	
-#	.set x_RAM_PPN_7, (x_DATA_BASE_ADDR + 7*PAGE_SZ)
-#	.set MMU_ini_dat_RAM7, (((x_RAM_PPN_7 >>12) <<6) | 0b000111) # d,v,g=1
-
 	
 	# read from MMU(6)
 	addi $1, $1, 1

cMIPS/vhdl/io.vhd

@@ -855,8 +855,8 @@ begin
         waiting    <= '0';
 
       when st_na =>
-        lcd_enable <= '0';              -- disable, stop waiting
-        lcd_read   <= '1';              --  hold inp data for 40ns
+        lcd_enable <= '0';              -- disable, still waiting
+        lcd_read   <= '1';
         waiting    <= '0';
 
       when st_nb =>

cMIPS/vhdl/packageWires.vhd

@@ -55,6 +55,7 @@ package p_WIRES is
   subtype reg19 is std_logic_vector(18 downto 0);
   subtype reg20 is std_logic_vector(19 downto 0);
   subtype reg21 is std_logic_vector(20 downto 0);
+  subtype reg23 is std_logic_vector(22 downto 0);
   subtype reg24 is std_logic_vector(23 downto 0);
   subtype reg28 is std_logic_vector(27 downto 0);
   subtype reg30 is std_logic_vector(29 downto 0);
@@ -166,6 +167,10 @@ package p_WIRES is
 
   type t_rimm_mem is array (0 to 31) of t_rimm_type;
 
+  -- type for floating point numbers: 'good' number, infinity, NaN, zero
+  type FP_type is (fp_is_good, fp_is_inf, fp_is_NaN, fp_is_zero);
+
+  
   function log2_ceil(n: natural) return natural;  
   function CONVERT_BOOLEAN(b: in boolean) return std_logic;
   function CONVERT_STRING(s: in string) return std_logic_vector;

cMIPS/vhdl/tb_cMIPS.vhd

@@ -139,6 +139,28 @@ architecture TB of tb_cMIPS is
           bit_rt  : out   std_logic_vector);-- communication speed - TB only
   end component simple_uart;
 
+  component FPU is
+    port (rst      : in   std_logic;
+          clk      : in   std_logic;
+          sel      : in   std_logic;
+          rdy      : out  std_logic;
+          wr       : in   std_logic;
+          addr     : in   std_logic_vector;
+          data_inp : in   std_logic_vector;
+          data_out : out  std_logic_vector);
+  end component FPU;
+
+  component fake_FPU is
+    port (rst      : in   std_logic;
+          clk      : in   std_logic;
+          sel      : in   std_logic;
+          rdy      : out  std_logic;
+          wr       : in   std_logic;
+          addr     : in   std_logic_vector;
+          data_inp : in   std_logic_vector;
+          data_out : out  std_logic_vector);
+  end component fake_FPU;
+
   component remota is
     generic(OUTPUT_FILE_NAME : string; INPUT_FILE_NAME : string);
     port(rst, clk  : in  std_logic;
@@ -478,7 +500,7 @@ begin  -- TB
   
   cpu_i_wait <= inst_wait;
   cpu_d_wait <= data_wait and io_wait;
-  io_wait    <= io_lcd_wait;  -- and io_fpu_wait;
+  io_wait    <= io_lcd_wait and io_fpu_wait;
 
   not_waiting <= (inst_wait and data_wait); --  and io_wait);
 
@@ -594,8 +616,10 @@ begin  -- TB
   U_uart_remota: remota generic map ("serial.out","serial.inp")
     port map (rst, clk, start_remota, uart_txd, uart_rxd, bit_rt);
 
-  -- U_FPU: FPU
-  -- port map (rst,clk, io_FPU_sel, io_FPU_wait, wr, d_addr, cpu_data);
+  -- U_FPU: fake_FPU
+  U_FPU: FPU
+    port map (rst,clk, io_FPU_sel,io_FPU_wait, wr, d_addr(5 downto 2),
+              cpu_data,fpu_d_out);
 
   -- U_sys_stats: sys_stats                -- CPU reads system counters
   --   port map (cpu_reset,clk, io_sstats_sel, wr, d_addr, sstats_d_out,
@@ -701,7 +725,7 @@ use work.p_wires.all;
 use work.p_memory.all;
 
 entity io_addr_decode is                -- CPU side triggers access
-  port (clk,rst     : in  std_logic;
+  port (clk,rst     : in  std_logic;    -- clk sparates back-to-back refs
         cpu_d_aVal  : in  std_logic;    -- CPU data addr valid (active=0)
         addr        : in  reg32;        -- CPU address
         dev_select  : out reg4;         -- select input to CPU

cMIPS/vhdl/units.vhd

@@ -669,7 +669,7 @@ begin
 
   w_d <= this xor cycle;                -- active for ONE cycle only
 
-  w <= not(w_d or sel);
+  w <= w_d and sel;
 
   waiting <= w and will_wait;