4 Author : Andrew Waterman, Yunsup Lee
8 Version : (under version control)
13 The RISC-V ISA Simulator implements a functional model of one or more
19 We assume that the RISCV environment variable is set to the RISC-V tools
20 install path, and that the riscv-fesvr package is installed there.
24 $ ../configure --prefix=$RISCV --with-fesvr=$RISCV
28 Compiling and Running a Simple C Program
29 -------------------------------------------
31 Install spike (see Build Steps), riscv-gnu-toolchain, and riscv-pk.
33 Write a short C program and name it hello.c. Then, compile it into a RISC-V
34 ELF binary named hello:
36 $ riscv64-unknown-elf-gcc -o hello hello.c
38 Now you can simulate the program atop the proxy kernel:
42 Simulating a New Instruction
43 ------------------------------------
45 Adding an instruction to the simulator requires two steps:
47 1. Describe the instruction's functional behavior in the file
48 riscv/insns/<new_instruction_name>.h. Examine other instructions
49 in that directory as a starting point.
51 2. Add the opcode and opcode mask to riscv/opcodes.h. Alternatively,
52 add it to the riscv-opcodes package, and it will do so for you:
55 $ vi opcodes // add a line for the new instruction
58 3. Rebuild the simulator.
60 Interactive Debug Mode
61 ---------------------------
63 To invoke interactive debug mode, launch spike with -d:
67 To see the contents of an integer register (0 is for core 0):
71 To see the contents of a floating point register:
79 depending upon whether you wish to print the register as single- or double-precision.
81 To see the contents of a memory location (physical address in hex):
85 To see the contents of memory with a virtual address (0 for core 0):
89 You can advance by one instruction by pressing <enter>. You can also
90 execute until a desired equality is reached:
92 : until pc 0 2020 (stop when pc=2020)
93 : until mem 2020 50a9907311096993 (stop when mem[2020]=50a9907311096993)
95 Alternatively, you can execute as long as an equality is true:
97 : while mem 2020 50a9907311096993
99 You can continue execution indefinitely by:
103 At any point during execution (even without -d), you can enter the
104 interactive debug mode with `<control>-<c>`.
106 To end the simulation from the debug prompt, press `<control>-<c>` or:
113 An alternative to interactive debug mode is to attach using gdb. When invoked
114 with '--gdb-port <port>' spike will listen on the given TCP port. It's
115 possible to attach with gdb (that has riscv support compiled in) by entering
116 `target remote localhost:<port>` in gdb. For example, in one shell run:
118 spike --gdb-port 9824 pk tests/debug
121 Then in a second shell you may do something like:
123 tnewsome@compy-vm:~/SiFive/riscv-isa-sim$ $RISCV/bin/riscv64-unknown-elf-gdb tests/debug
124 GNU gdb (GDB) 7.11.50.20160212-git
125 Copyright (C) 2016 Free Software Foundation, Inc.
126 License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
127 This is free software: you are free to change and redistribute it.
128 There is NO WARRANTY, to the extent permitted by law. Type "show copying"
129 and "show warranty" for details.
130 This GDB was configured as "--host=x86_64-pc-linux-gnu --target=riscv64-unknown-elf".
131 Type "show configuration" for configuration details.
132 For bug reporting instructions, please see:
133 <http://www.gnu.org/software/gdb/bugs/>.
134 Find the GDB manual and other documentation resources online at:
135 <http://www.gnu.org/software/gdb/documentation/>.
136 For help, type "help".
137 Type "apropos word" to search for commands related to "word"...
138 Reading symbols from tests/debug...done.
139 (gdb) target remote localhost:9824
140 Remote debugging using localhost:9824
141 0x00000000000101f0 in main ()
142 at /home/tnewsome/SiFive/riscv-isa-sim/tests/debug.c:20
147 15 volatile int i = 42;
148 16 const char *text = "constant\n";
149 17 int threshold = 7;
151 19 // Wait for the debugger to get us out of this loop.
155 23 printf("%s", text);
156 24 for (int y=0; y < 10; y++) {
160 Breakpoint 1 at 0x10178: file /home/tnewsome/SiFive/riscv-isa-sim/tests/debug.c, line 7.
164 Breakpoint 1, print_row (length=0)
165 at /home/tnewsome/SiFive/riscv-isa-sim/tests/debug.c:7
166 7 for (int x=0; x<length; x++) {
170 Breakpoint 1, print_row (length=1)
171 at /home/tnewsome/SiFive/riscv-isa-sim/tests/debug.c:7
172 7 for (int x=0; x<length; x++) {
173 (gdb) delete breakpoints
174 Delete all breakpoints? (y or n) y
177 Remote connection closed