-RISC-V ISA Simulator
-======================
-
-Author : Andrew Waterman, Yunsup Lee
-
-Date : June 19, 2011
-
-Version : (under version control)
+Spike RISC-V ISA Simulator
+============================
About
-------------
-The RISC-V ISA Simulator implements a functional model of one or more
+Spike, the RISC-V ISA Simulator, implements a functional model of one or more
RISC-V processors.
+Spike is named after the golden spike used to celebrate the completion of the
+US transcontinental railway.
+
Build Steps
---------------
We assume that the RISCV environment variable is set to the RISC-V tools
install path, and that the riscv-fesvr package is installed there.
+ $ apt-get install device-tree-compiler
$ mkdir build
$ cd build
$ ../configure --prefix=$RISCV --with-fesvr=$RISCV
Debugging With Gdb
------------------
-An alternative to interactive debug mode is to attach using gdb. When invoked
-with '--gdb-port <port>' spike will listen on the given TCP port. It's
-possible to attach with gdb (that has riscv support compiled in) by entering
-`target remote localhost:<port>` in gdb. For example, in one shell run:
+An alternative to interactive debug mode is to attach using gdb. Because spike
+tries to be like real hardware, you also need OpenOCD to do that. OpenOCD
+doesn't currently know about address translation, so it's not possible to
+easily debug programs that are run under `pk`. We'll use the following test
+program:
+```
+$ cat rot13.c
+char text[] = "Vafgehpgvba frgf jnag gb or serr!";
+
+// Don't use the stack, because sp isn't set up.
+volatile int wait = 1;
+
+int main()
+{
+ while (wait)
+ ;
+
+ // Doesn't actually go on the stack, because there are lots of GPRs.
+ int i = 0;
+ while (text[i]) {
+ char lower = text[i] | 32;
+ if (lower >= 'a' && lower <= 'm')
+ text[i] += 13;
+ else if (lower > 'm' && lower <= 'z')
+ text[i] -= 13;
+ i++;
+ }
+
+ while (!wait)
+ ;
+}
+$ cat spike.lds
+OUTPUT_ARCH( "riscv" )
+
+SECTIONS
+{
+ . = 0x10010000;
+ .text : { *(.text) }
+ .data : { *(.data) }
+}
+$ riscv64-unknown-elf-gcc -g -Og -o rot13-64.o -c rot13.c
+$ riscv64-unknown-elf-gcc -g -Og -T spike.lds -nostartfiles -o rot13-64 rot13-64.o
+```
+
+To debug this program, first run spike telling it to listen for OpenOCD:
```
-spike --gdb-port 9824 pk tests/debug
+$ spike --rbb-port=9824 -m0x10000000:0x20000 rot13-64
+Listening for remote bitbang connection on port 9824.
```
-Then in a second shell you may do something like:
+In a separate shell run OpenOCD with the appropriate configuration file:
```
-tnewsome@compy-vm:~/SiFive/riscv-isa-sim$ $RISCV/bin/riscv64-unknown-elf-gdb tests/debug
-GNU gdb (GDB) 7.11.50.20160212-git
+$ cat spike.cfg
+interface remote_bitbang
+remote_bitbang_host localhost
+remote_bitbang_port 9824
+
+set _CHIPNAME riscv
+jtag newtap $_CHIPNAME cpu -irlen 5 -expected-id 0x10e31913
+
+set _TARGETNAME $_CHIPNAME.cpu
+target create $_TARGETNAME riscv -chain-position $_TARGETNAME
+
+gdb_report_data_abort enable
+
+init
+halt
+$ openocd -f spike.cfg
+Open On-Chip Debugger 0.10.0-dev-00002-gc3b344d (2017-06-08-12:14)
+...
+riscv.cpu: target state: halted
+```
+
+In yet another shell, start your gdb debug session:
+```
+tnewsome@compy-vm:~/SiFive/spike-test$ riscv64-unknown-elf-gdb rot13-64
+GNU gdb (GDB) 7.12.50.20170505-git
Copyright (C) 2016 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word"...
-Reading symbols from tests/debug...done.
-(gdb) target remote localhost:9824
-Remote debugging using localhost:9824
-0x00000000000101f0 in main ()
- at /home/tnewsome/SiFive/riscv-isa-sim/tests/debug.c:20
-20 while (i)
-(gdb) p i
-$1 = 42
-(gdb) list
-15 volatile int i = 42;
-16 const char *text = "constant\n";
-17 int threshold = 7;
-18
-19 // Wait for the debugger to get us out of this loop.
-20 while (i)
-21 ;
-22
-23 printf("%s", text);
-24 for (int y=0; y < 10; y++) {
-(gdb) p i=0
+Reading symbols from rot13-64...done.
+(gdb) target remote localhost:3333
+Remote debugging using localhost:3333
+0x000000001001000a in main () at rot13.c:8
+8 while (wait)
+(gdb) print wait
+$1 = 1
+(gdb) print wait=0
$2 = 0
-(gdb) b print_row
-Breakpoint 1 at 0x10178: file /home/tnewsome/SiFive/riscv-isa-sim/tests/debug.c, line 7.
+(gdb) print text
+$3 = "Vafgehpgvba frgf jnag gb or serr!"
+(gdb) b 23
+Breakpoint 1 at 0x10010064: file rot13.c, line 23.
(gdb) c
Continuing.
-Breakpoint 1, print_row (length=0)
- at /home/tnewsome/SiFive/riscv-isa-sim/tests/debug.c:7
-7 for (int x=0; x<length; x++) {
-(gdb) c
-Continuing.
-
-Breakpoint 1, print_row (length=1)
- at /home/tnewsome/SiFive/riscv-isa-sim/tests/debug.c:7
-7 for (int x=0; x<length; x++) {
-(gdb) delete breakpoints
-Delete all breakpoints? (y or n) y
-(gdb) c
-Continuing.
-Remote connection closed
-(gdb)
+Breakpoint 1, main () at rot13.c:23
+23 while (!wait)
+(gdb) print wait
+$4 = 0
+(gdb) print text
+...
```
projects / riscv-isa-sim.git / blobdiff