From d1d7e39da76bc751c35a62b994d004c405ebc849 Mon Sep 17 00:00:00 2001
From: Roberto Hexsel <roberto@inf.ufpr.br>
Date: Sat, 14 Nov 2015 13:10:42 -0200
Subject: [PATCH] yet another RAM address decoding scheme
---
cMIPS/bin/run.sh | 8 ++++----
cMIPS/include/start.s | 4 ++--
cMIPS/tests/busError_i.s | 28 ++++++++++++++++++++++++++++
cMIPS/tests/doTests.sh | 6 +++---
cMIPS/tests/echo.c | 8 +++-----
cMIPS/tests/stdin_out.s | 3 +++
cMIPS/vhdl/core.vhd | 4 +---
cMIPS/vhdl/tb_cMIPS.vhd | 27 ++++++++++++++++++++++++---
8 files changed, 68 insertions(+), 20 deletions(-)
diff --git a/cMIPS/bin/run.sh b/cMIPS/bin/run.sh
index 0e0a33c..7600998 100755
--- a/cMIPS/bin/run.sh
+++ b/cMIPS/bin/run.sh
@@ -1,7 +1,7 @@
#!/bin/bash
## ------------------------------------------------------------------------
-## classicalMIPS, Roberto Hexsel, 23nov2012-12nov2015
+## classicalMIPS, Roberto Hexsel, 23nov2012-13nov2015
## ------------------------------------------------------------------------
# set -x
@@ -89,11 +89,11 @@ if [ -v $WAVE ] ; then
else
- ## this echo is for testing the reads from stdin
- ## echo -en "abc\n%" |
- "${simulator}" $options ; gtkwave -O /dev/null ${visual} ${sav}
+ "${simulator}" $options ; gtkwave -O /dev/null ${visual} ${sav} &
fi
+
+
# --wave=${visual%.vcd}.ghw
diff --git a/cMIPS/include/start.s b/cMIPS/include/start.s
index 747e661..fdc6747 100644
--- a/cMIPS/include/start.s
+++ b/cMIPS/include/start.s
@@ -75,8 +75,8 @@ _start:
li $k0, 4
mtc0 $k0, cop0_Wired
- # initialize SP at top of RAM: ramTop - 8
- li $sp, ((x_DATA_BASE_ADDR+x_DATA_MEM_SZ) - 8)
+ # initialize SP at top of RAM: ramTop - 16
+ li $sp, ((x_DATA_BASE_ADDR+x_DATA_MEM_SZ) - 16)
# set STATUS, cop0, hw interrupt IRQ7,IRQ6,IRQ5 enabled, user mode
li $k0, 0x1000e011
diff --git a/cMIPS/tests/busError_i.s b/cMIPS/tests/busError_i.s
index 4cc0b54..b1f6957 100644
--- a/cMIPS/tests/busError_i.s
+++ b/cMIPS/tests/busError_i.s
@@ -2,6 +2,9 @@
## generate and handle (??) a instruction fetch bus error
## the error occurs on an attempt to fetch from non-exixting ROM
##
+ ## one TLB entry must point into the non-existing ROM address to
+ ## avoid a TLBmiss exception.
+ ##
.include "cMIPS.s"
.text
@@ -9,6 +12,7 @@
.set noreorder
.global _start, _exit
.ent _start
+
_start: nop
li $sp,(x_DATA_BASE_ADDR+x_DATA_MEM_SZ-8) # initialize SP: ramTop-8
@@ -16,6 +20,30 @@ _start: nop
li $k0, 0x10000010
mtc0 $k0, cop0_STATUS
+ .set bad_address, (x_INST_BASE_ADDR + x_INST_MEM_SZ + 4096)
+
+ # get physical page number for 2 pages above top of ROM
+ # then write it to TLB[3]
+
+ li $a0, ( bad_address >>12 )
+ sll $a2, $a0, 12 # tag for RAM[8,9] double-page
+ mtc0 $a2, cop0_EntryHi
+
+ li $a0, ((bad_address + 0*4096) >>12 )
+ sll $a1, $a0, 6 # ROM_top+4096 (even)
+ ori $a1, $a1, 0b00000000000000000000000000000111 # ccc=0, d,v,g1
+ mtc0 $a1, cop0_EntryLo0
+
+ li $a0, ((bad_address + 1*4096) >>12 )
+ sll $a1, $a0, 6 # ROM_top+8192 (odd)
+ ori $a1, $a1, 0b00000000000000000000000000000111 # ccc=0, d,v,g1
+ mtc0 $a1, cop0_EntryLo1
+
+ # and write it to TLB[3]
+ li $k0, 3
+ mtc0 $k0, cop0_Index
+ tlbwi
+
j main
nop
diff --git a/cMIPS/tests/doTests.sh b/cMIPS/tests/doTests.sh
index 8b7c9d8..36ab14c 100755
--- a/cMIPS/tests/doTests.sh
+++ b/cMIPS/tests/doTests.sh
@@ -67,7 +67,7 @@ a_FWD="fwdAddAddAddSw fwd_SW lwFWDsw lwFWDsw2 slt32 slt_u_32 slt_s_32 reg0"
a_CAC="dCacheTst lhUshUCache lbUsbUCache lbsbCache dCacheTstH dCacheTstB"
a_BEQ="lw-bne bXtz sltbeq beq_dlySlot jr_dlySlot"
a_FUN="jaljr jr_2 jal_fun_jr jalr_jr bltzal_fun_jr"
-a_OTH="mult div mul sll slr movz wsbh_seb extract insert"
+a_OTH="mult div mul sll slr movz wsbh_seb extract insert"
a_BHW="lbsb lhsh lwsw lwswIncr swlw lwl_lwr"
a_MEM="lwSweepRAM"
a_CTR="teq_tne teq_jal teq_lw tlt_tlti tltu_tgeu eiDI ll_sc overflow counter"
@@ -88,7 +88,7 @@ stoptime=20ms
if [ 0 = 0 ] ; then
for F in $(echo $a_FWD $a_CAC $a_BEQ $a_FUN $a_OTH $a_BHW $a_MEM $a_CTR $a_COP $a_MMU $a_EXC $a_IOs);
do
- $bin/assemble.sh ${F}.s
+ $bin/assemble.sh ${F}.s || exit 1
${simulator} --ieee-asserts=disable --stop-time=$stoptime \
2>/dev/null >$F.simout
diff $ignBLANKS -q $F.expected $F.simout
@@ -132,7 +132,7 @@ else
fi
for F in $(echo "$SIMULATE" ) ; do
- $bin/compile.sh -O 3 ${F}.c
+ $bin/compile.sh -O 3 ${F}.c || exit 1
${simulator} --ieee-asserts=disable --stop-time=$stoptime \
2>/dev/null >$F.simout
diff $ignBLANKS -q $F.expected $F.simout
diff --git a/cMIPS/tests/echo.c b/cMIPS/tests/echo.c
index c56ea34..218de29 100644
--- a/cMIPS/tests/echo.c
+++ b/cMIPS/tests/echo.c
@@ -1,6 +1,6 @@
// Test stdin and stdout -- echo characters read from stdin to stdout
-// test ends when '%' (percent) is read.
-// from_stdin() returns EOT (0x04) the there is nothing on stdin
+// test ends when '%' (percent) is read/typed.
+// from_stdin() returns LF (0x0a) the there is nothing on stdin
//
// Keep in mind that the terminal itself does echoing -- characters are
// displayed AFTER a second NewLine because of the terminal also echoes
@@ -19,9 +19,7 @@ void main(void) {
c = (char)from_stdin();
- if (c != (char)0x04) { // EOT
- to_stdout(c);
- }
+ to_stdout(c);
} while (c != '%');
diff --git a/cMIPS/tests/stdin_out.s b/cMIPS/tests/stdin_out.s
index 8a8a54c..2d083e8 100644
--- a/cMIPS/tests/stdin_out.s
+++ b/cMIPS/tests/stdin_out.s
@@ -1,3 +1,6 @@
+# Test stdin and stdout -- echo characters read from stdin to stdout
+# test ends when '%' (percent) is read/typed.
+
.include "cMIPS.s"
.text
.align 2
diff --git a/cMIPS/vhdl/core.vhd b/cMIPS/vhdl/core.vhd
index e714031..b966cbc 100644
--- a/cMIPS/vhdl/core.vhd
+++ b/cMIPS/vhdl/core.vhd
@@ -73,8 +73,6 @@ architecture rtl of core is
EX_can_trap: out std_logic_vector;
RF_exception: in exception_type;
EX_exception: out exception_type;
--- RF_trap_instr: in instr_type;
--- EX_trap_instr: out instr_type;
RF_is_delayslot: in std_logic;
EX_is_delayslot: out std_logic;
RF_PC_abort: in boolean;
@@ -85,7 +83,7 @@ architecture rtl of core is
EX_trapped: out boolean);
end component reg_excp_RF_EX;
- component reg_excp_EX_MM is -- jjjjj
+ component reg_excp_EX_MM is
port(clk, rst, ld: in std_logic;
EX_cop0_reg: in reg5;
MM_cop0_reg: out reg5;
diff --git a/cMIPS/vhdl/tb_cMIPS.vhd b/cMIPS/vhdl/tb_cMIPS.vhd
index e6fff99..1fca33f 100644
--- a/cMIPS/vhdl/tb_cMIPS.vhd
+++ b/cMIPS/vhdl/tb_cMIPS.vhd
@@ -750,6 +750,14 @@ architecture behavioral of ram_addr_decode is
constant r_mask : std_logic_vector := r_hi & r_lo;
signal in_range : boolean;
+
+ constant RAM_ADDR_BOTTOM : natural :=
+ to_integer(signed(x_DATA_BASE_ADDR(HI_SEL_BITS downto LO_SEL_BITS)));
+ constant RAM_ADDR_RANGE : natural :=
+ (to_integer(signed(x_DATA_BASE_ADDR(HI_SEL_BITS downto LO_SEL_BITS)))
+ +
+ to_integer(signed(x_DATA_MEM_SZ(HI_SEL_BITS downto LO_SEL_BITS))));
+ constant RAM_ADDR_TOP : natural := RAM_ADDR_BOTTOM + RAM_ADDR_RANGE;
begin
@@ -757,9 +765,22 @@ begin
-- and ((addr and a_mask) = x_DATA_BASE_ADDR)
-- and ((addr and r_mask) = x_DATA_BASE_ADDR) );
- in_range <= ( addr(HI_SEL_BITS downto LO_SEL_BITS)
- =
- x_DATA_BASE_ADDR(HI_SEL_BITS downto LO_SEL_BITS) );
+-- this works only for small RAMS
+-- in_range <= ( addr(HI_SEL_BITS downto LO_SEL_BITS)
+-- =
+-- x_DATA_BASE_ADDR(HI_SEL_BITS downto LO_SEL_BITS) );
+
+
+ -- this is ONLY acceptable for simulations;
+ -- computing these differences is TOO expensive for synthesis
+ in_range <= ( (to_integer(signed(addr(HI_SEL_BITS downto LO_SEL_BITS)))
+ >=
+ RAM_ADDR_BOTTOM)
+ and
+ (to_integer(signed(addr(HI_SEL_BITS downto LO_SEL_BITS)))
+ <
+ RAM_ADDR_TOP)
+ );
aVal <= '0' when (rst = '1' and cpu_d_aVal = '0' and in_range) else '1';
--
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