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binutils-gdb/sim/example-synacor/sim-main.c
Andrew Burgess 1d506c26d9 Update copyright year range in header of all files managed by GDB 
This commit is the result of the following actions:

  - Running gdb/copyright.py to update all of the copyright headers to
    include 2024,

  - Manually updating a few files the copyright.py script told me to
    update, these files had copyright headers embedded within the
    file,

  - Regenerating gdbsupport/Makefile.in to refresh it's copyright
    date,

  - Using grep to find other files that still mentioned 2023.  If
    these files were updated last year from 2022 to 2023 then I've
    updated them this year to 2024.

I'm sure I've probably missed some dates.  Feel free to fix them up as
you spot them.
2024-01-12 15:49:57 +00:00

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/* Example synacor simulator.
Copyright (C) 2005-2024 Free Software Foundation, Inc.
Contributed by Mike Frysinger.
This file is part of simulators.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
/* This file contains the main simulator decoding logic. i.e. everything that
is architecture specific. */
/* This must come before any other includes. */
#include "defs.h"
#include "sim-main.h"
#include "sim-signal.h"
#include "example-synacor-sim.h"
/* Get the register number from the number. */
static uint16_t
register_num (SIM_CPU *cpu, uint16_t num)
{
SIM_DESC sd = CPU_STATE (cpu);
if (num < 0x8000 || num >= 0x8008)
sim_engine_halt (sd, cpu, NULL, sim_pc_get (cpu), sim_signalled, SIM_SIGILL);
return num & 0xf;
}
/* Helper to process immediates according to the ISA. */
static uint16_t
interp_num (SIM_CPU *cpu, uint16_t num)
{
SIM_DESC sd = CPU_STATE (cpu);
struct example_sim_cpu *example_cpu = EXAMPLE_SIM_CPU (cpu);
if (num < 0x8000)
{
/* Numbers 0..32767 mean a literal value. */
TRACE_DECODE (cpu, "%#x is a literal", num);
return num;
}
else if (num < 0x8008)
{
/* Numbers 32768..32775 instead mean registers 0..7. */
TRACE_DECODE (cpu, "%#x is register R%i", num, num & 0xf);
return example_cpu->regs[num & 0xf];
}
else
{
/* Numbers 32776..65535 are invalid. */
TRACE_DECODE (cpu, "%#x is an invalid number", num);
sim_engine_halt (sd, cpu, NULL, example_cpu->pc, sim_signalled, SIM_SIGILL);
}
}
/* Decode & execute a single instruction. */
void step_once (SIM_CPU *cpu)
{
SIM_DESC sd = CPU_STATE (cpu);
struct example_sim_cpu *example_cpu = EXAMPLE_SIM_CPU (cpu);
uint16_t iw1, num1;
sim_cia pc = sim_pc_get (cpu);
iw1 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc);
TRACE_EXTRACT (cpu, "%04x: iw1: %#x", pc, iw1);
/* This never happens, but technically is possible in the ISA. */
num1 = interp_num (cpu, iw1);
if (num1 == 0)
{
/* halt: 0: Stop execution and terminate the program. */
TRACE_INSN (cpu, "HALT");
sim_engine_halt (sd, cpu, NULL, pc, sim_exited, 0);
}
else if (num1 == 1)
{
/* set: 1 a b: Set register <a> to the value of <b>. */
uint16_t iw2, iw3, num2, num3;
iw2 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 2);
num2 = register_num (cpu, iw2);
iw3 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 4);
num3 = interp_num (cpu, iw3);
TRACE_EXTRACT (cpu, "SET %#x %#x", iw2, iw3);
TRACE_INSN (cpu, "SET R%i %#x", num2, num3);
TRACE_REGISTER (cpu, "R%i = %#x", num2, num3);
example_cpu->regs[num2] = num3;
pc += 6;
}
else if (num1 == 2)
{
/* push: 2 a: Push <a> onto the stack. */
uint16_t iw2, num2;
iw2 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 2);
num2 = interp_num (cpu, iw2);
TRACE_EXTRACT (cpu, "PUSH %#x", iw2);
TRACE_INSN (cpu, "PUSH %#x", num2);
sim_core_write_aligned_2 (cpu, pc, write_map, example_cpu->sp, num2);
example_cpu->sp -= 2;
TRACE_REGISTER (cpu, "SP = %#x", example_cpu->sp);
pc += 4;
}
else if (num1 == 3)
{
/* pop: 3 a: Remove the top element from the stack and write it into <a>.
Empty stack = error. */
uint16_t iw2, num2, result;
iw2 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 2);
num2 = register_num (cpu, iw2);
TRACE_EXTRACT (cpu, "POP %#x", iw2);
TRACE_INSN (cpu, "POP R%i", num2);
example_cpu->sp += 2;
TRACE_REGISTER (cpu, "SP = %#x", example_cpu->sp);
result = sim_core_read_aligned_2 (cpu, pc, read_map, example_cpu->sp);
TRACE_REGISTER (cpu, "R%i = %#x", num2, result);
example_cpu->regs[num2] = result;
pc += 4;
}
else if (num1 == 4)
{
/* eq: 4 a b c: Set <a> to 1 if <b> is equal to <c>; set it to 0
otherwise. */
uint16_t iw2, iw3, iw4, num2, num3, num4, result;
iw2 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 2);
num2 = register_num (cpu, iw2);
iw3 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 4);
num3 = interp_num (cpu, iw3);
iw4 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 6);
num4 = interp_num (cpu, iw4);
result = (num3 == num4);
TRACE_EXTRACT (cpu, "EQ %#x %#x %#x", iw2, iw3, iw4);
TRACE_INSN (cpu, "EQ R%i %#x %#x", num2, num3, num4);
TRACE_DECODE (cpu, "R%i = (%#x == %#x) = %i", num2, num3, num4, result);
TRACE_REGISTER (cpu, "R%i = %#x", num2, result);
example_cpu->regs[num2] = result;
pc += 8;
}
else if (num1 == 5)
{
/* gt: 5 a b c: Set <a> to 1 if <b> is greater than <c>; set it to 0
otherwise. */
uint16_t iw2, iw3, iw4, num2, num3, num4, result;
iw2 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 2);
num2 = register_num (cpu, iw2);
iw3 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 4);
num3 = interp_num (cpu, iw3);
iw4 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 6);
num4 = interp_num (cpu, iw4);
result = (num3 > num4);
TRACE_EXTRACT (cpu, "GT %#x %#x %#x", iw2, iw3, iw4);
TRACE_INSN (cpu, "GT R%i %#x %#x", num2, num3, num4);
TRACE_DECODE (cpu, "R%i = (%#x > %#x) = %i", num2, num3, num4, result);
TRACE_REGISTER (cpu, "R%i = %#x", num2, result);
example_cpu->regs[num2] = result;
pc += 8;
}
else if (num1 == 6)
{
/* jmp: 6 a: Jump to <a>. */
uint16_t iw2, num2;
iw2 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 2);
num2 = interp_num (cpu, iw2);
/* Addresses are 16-bit aligned. */
num2 <<= 1;
TRACE_EXTRACT (cpu, "JMP %#x", iw2);
TRACE_INSN (cpu, "JMP %#x", num2);
pc = num2;
TRACE_BRANCH (cpu, "JMP %#x", pc);
}
else if (num1 == 7)
{
/* jt: 7 a b: If <a> is nonzero, jump to <b>. */
uint16_t iw2, iw3, num2, num3;
iw2 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 2);
num2 = interp_num (cpu, iw2);
iw3 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 4);
num3 = interp_num (cpu, iw3);
/* Addresses are 16-bit aligned. */
num3 <<= 1;
TRACE_EXTRACT (cpu, "JT %#x %#x", iw2, iw3);
TRACE_INSN (cpu, "JT %#x %#x", num2, num3);
TRACE_DECODE (cpu, "JT %#x != 0 -> %s", num2, num2 ? "taken" : "nop");
if (num2)
{
pc = num3;
TRACE_BRANCH (cpu, "JT %#x", pc);
}
else
pc += 6;
}
else if (num1 == 8)
{
/* jf: 8 a b: If <a> is zero, jump to <b>. */
uint16_t iw2, iw3, num2, num3;
iw2 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 2);
num2 = interp_num (cpu, iw2);
iw3 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 4);
num3 = interp_num (cpu, iw3);
/* Addresses are 16-bit aligned. */
num3 <<= 1;
TRACE_EXTRACT (cpu, "JF %#x %#x", iw2, iw3);
TRACE_INSN (cpu, "JF %#x %#x", num2, num3);
TRACE_DECODE (cpu, "JF %#x == 0 -> %s", num2, num2 ? "nop" : "taken");
if (!num2)
{
pc = num3;
TRACE_BRANCH (cpu, "JF %#x", pc);
}
else
pc += 6;
}
else if (num1 == 9)
{
/* add: 9 a b c: Assign <a> the sum of <b> and <c> (modulo 32768). */
uint16_t iw2, iw3, iw4, num2, num3, num4, result;
iw2 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 2);
num2 = register_num (cpu, iw2);
iw3 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 4);
num3 = interp_num (cpu, iw3);
iw4 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 6);
num4 = interp_num (cpu, iw4);
result = (num3 + num4) % 32768;
TRACE_EXTRACT (cpu, "ADD %#x %#x %#x", iw2, iw3, iw4);
TRACE_INSN (cpu, "ADD R%i %#x %#x", num2, num3, num4);
TRACE_DECODE (cpu, "R%i = (%#x + %#x) %% %i = %#x", num2, num3, num4,
32768, result);
TRACE_REGISTER (cpu, "R%i = %#x", num2, result);
example_cpu->regs[num2] = result;
pc += 8;
}
else if (num1 == 10)
{
/* mult: 10 a b c: Store into <a> the product of <b> and <c> (modulo
32768). */
uint16_t iw2, iw3, iw4, num2, num3, num4, result;
iw2 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 2);
num2 = register_num (cpu, iw2);
iw3 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 4);
num3 = interp_num (cpu, iw3);
iw4 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 6);
num4 = interp_num (cpu, iw4);
result = (num3 * num4) % 32768;
TRACE_EXTRACT (cpu, "MULT %#x %#x %#x", iw2, iw3, iw4);
TRACE_INSN (cpu, "MULT R%i %#x %#x", num2, num3, num4);
TRACE_DECODE (cpu, "R%i = (%#x * %#x) %% %i = %#x", num2, num3, num4,
32768, result);
TRACE_REGISTER (cpu, "R%i = %#x", num2, result);
example_cpu->regs[num2] = result;
pc += 8;
}
else if (num1 == 11)
{
/* mod: 11 a b c: Store into <a> the remainder of <b> divided by <c>. */
uint16_t iw2, iw3, iw4, num2, num3, num4, result;
iw2 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 2);
num2 = register_num (cpu, iw2);
iw3 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 4);
num3 = interp_num (cpu, iw3);
iw4 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 6);
num4 = interp_num (cpu, iw4);
result = num3 % num4;
TRACE_EXTRACT (cpu, "MOD %#x %#x %#x", iw2, iw3, iw4);
TRACE_INSN (cpu, "MOD R%i %#x %#x", num2, num3, num4);
TRACE_DECODE (cpu, "R%i = %#x %% %#x = %#x", num2, num3, num4, result);
TRACE_REGISTER (cpu, "R%i = %#x", num2, result);
example_cpu->regs[num2] = result;
pc += 8;
}
else if (num1 == 12)
{
/* and: 12 a b c: Stores into <a> the bitwise and of <b> and <c>. */
uint16_t iw2, iw3, iw4, num2, num3, num4, result;
iw2 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 2);
num2 = register_num (cpu, iw2);
iw3 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 4);
num3 = interp_num (cpu, iw3);
iw4 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 6);
num4 = interp_num (cpu, iw4);
result = (num3 & num4);
TRACE_EXTRACT (cpu, "AND %#x %#x %#x", iw2, iw3, iw4);
TRACE_INSN (cpu, "AND R%i %#x %#x", num2, num3, num4);
TRACE_DECODE (cpu, "R%i = %#x & %#x = %#x", num2, num3, num4, result);
TRACE_REGISTER (cpu, "R%i = %#x", num2, result);
example_cpu->regs[num2] = result;
pc += 8;
}
else if (num1 == 13)
{
/* or: 13 a b c: Stores into <a> the bitwise or of <b> and <c>. */
uint16_t iw2, iw3, iw4, num2, num3, num4, result;
iw2 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 2);
num2 = register_num (cpu, iw2);
iw3 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 4);
num3 = interp_num (cpu, iw3);
iw4 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 6);
num4 = interp_num (cpu, iw4);
result = (num3 | num4);
TRACE_EXTRACT (cpu, "OR %#x %#x %#x", iw2, iw3, iw4);
TRACE_INSN (cpu, "OR R%i %#x %#x", num2, num3, num4);
TRACE_DECODE (cpu, "R%i = %#x | %#x = %#x", num2, num3, num4, result);
TRACE_REGISTER (cpu, "R%i = %#x", num2, result);
example_cpu->regs[num2] = result;
pc += 8;
}
else if (num1 == 14)
{
/* not: 14 a b: Stores 15-bit bitwise inverse of <b> in <a>. */
uint16_t iw2, iw3, num2, num3, result;
iw2 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 2);
num2 = register_num (cpu, iw2);
iw3 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 4);
num3 = interp_num (cpu, iw3);
result = (~num3) & 0x7fff;
TRACE_EXTRACT (cpu, "NOT %#x %#x", iw2, iw3);
TRACE_INSN (cpu, "NOT R%i %#x", num2, num3);
TRACE_DECODE (cpu, "R%i = (~%#x) & 0x7fff = %#x", num2, num3, result);
TRACE_REGISTER (cpu, "R%i = %#x", num2, result);
example_cpu->regs[num2] = result;
pc += 6;
}
else if (num1 == 15)
{
/* rmem: 15 a b: Read memory at address <b> and write it to <a>. */
uint16_t iw2, iw3, num2, num3, result;
iw2 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 2);
num2 = register_num (cpu, iw2);
iw3 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 4);
num3 = interp_num (cpu, iw3);
/* Addresses are 16-bit aligned. */
num3 <<= 1;
TRACE_EXTRACT (cpu, "RMEM %#x %#x", iw2, iw3);
TRACE_INSN (cpu, "RMEM R%i %#x", num2, num3);
TRACE_MEMORY (cpu, "reading %#x", num3);
result = sim_core_read_aligned_2 (cpu, pc, read_map, num3);
TRACE_REGISTER (cpu, "R%i = %#x", num2, result);
example_cpu->regs[num2] = result;
pc += 6;
}
else if (num1 == 16)
{
/* wmem: 16 a b: Write the value from <b> into memory at address <a>. */
uint16_t iw2, iw3, num2, num3;
iw2 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 2);
num2 = interp_num (cpu, iw2);
iw3 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 4);
num3 = interp_num (cpu, iw3);
/* Addresses are 16-bit aligned. */
num2 <<= 1;
TRACE_EXTRACT (cpu, "WMEM %#x %#x", iw2, iw3);
TRACE_INSN (cpu, "WMEM %#x %#x", num2, num3);
TRACE_MEMORY (cpu, "writing %#x to %#x", num3, num2);
sim_core_write_aligned_2 (cpu, pc, write_map, num2, num3);
pc += 6;
}
else if (num1 == 17)
{
/* call: 17 a: Write the address of the next instruction to the stack and
jump to <a>. */
uint16_t iw2, num2;
iw2 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 2);
num2 = interp_num (cpu, iw2);
/* Addresses are 16-bit aligned. */
num2 <<= 1;
TRACE_EXTRACT (cpu, "CALL %#x", iw2);
TRACE_INSN (cpu, "CALL %#x", num2);
TRACE_MEMORY (cpu, "pushing %#x onto stack", (pc + 4) >> 1);
sim_core_write_aligned_2 (cpu, pc, write_map, example_cpu->sp, (pc + 4) >> 1);
example_cpu->sp -= 2;
TRACE_REGISTER (cpu, "SP = %#x", example_cpu->sp);
pc = num2;
TRACE_BRANCH (cpu, "CALL %#x", pc);
}
else if (num1 == 18)
{
/* ret: 18: Remove the top element from the stack and jump to it; empty
stack = halt. */
uint16_t result;
TRACE_INSN (cpu, "RET");
example_cpu->sp += 2;
TRACE_REGISTER (cpu, "SP = %#x", example_cpu->sp);
result = sim_core_read_aligned_2 (cpu, pc, read_map, example_cpu->sp);
TRACE_MEMORY (cpu, "popping %#x off of stack", result << 1);
pc = result << 1;
TRACE_BRANCH (cpu, "RET -> %#x", pc);
}
else if (num1 == 19)
{
/* out: 19 a: Write the character <a> to the terminal. */
uint16_t iw2, num2;
iw2 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 2);
num2 = interp_num (cpu, iw2);
TRACE_EXTRACT (cpu, "OUT %#x", iw2);
TRACE_INSN (cpu, "OUT %#x", num2);
TRACE_EVENTS (cpu, "write to stdout: %#x (%c)", num2, num2);
sim_io_printf (sd, "%c", num2);
pc += 4;
}
else if (num1 == 20)
{
/* in: 20 a: read a character from the terminal and write its ascii code
to <a>. It can be assumed that once input starts, it will continue
until a newline is encountered. This means that you can safely read
lines from the keyboard and trust that they will be fully read. */
uint16_t iw2, num2;
char c;
iw2 = sim_core_read_aligned_2 (cpu, pc, exec_map, pc + 2);
num2 = register_num (cpu, iw2);
TRACE_EXTRACT (cpu, "IN %#x", iw2);
TRACE_INSN (cpu, "IN %#x", num2);
sim_io_read_stdin (sd, &c, 1);
TRACE_EVENTS (cpu, "read from stdin: %#x (%c)", c, c);
/* The challenge uses lowercase for all inputs, so insert some low level
helpers of our own to make it a bit nicer. */
switch (c)
{
case 'Q':
sim_engine_halt (sd, cpu, NULL, pc, sim_exited, 0);
break;
}
TRACE_REGISTER (cpu, "R%i = %#x", iw2 & 0xf, c);
example_cpu->regs[iw2 & 0xf] = c;
pc += 4;
}
else if (num1 == 21)
{
/* noop: 21: no operation */
TRACE_INSN (cpu, "NOOP");
pc += 2;
}
else
sim_engine_halt (sd, cpu, NULL, pc, sim_signalled, SIM_SIGILL);
TRACE_REGISTER (cpu, "PC = %#x", pc);
sim_pc_set (cpu, pc);
}
/* Return the program counter for this cpu. */
static sim_cia
pc_get (sim_cpu *cpu)
{
struct example_sim_cpu *example_cpu = EXAMPLE_SIM_CPU (cpu);
return example_cpu->pc;
}
/* Set the program counter for this cpu to the new pc value. */
static void
pc_set (sim_cpu *cpu, sim_cia pc)
{
struct example_sim_cpu *example_cpu = EXAMPLE_SIM_CPU (cpu);
example_cpu->pc = pc;
}
/* Initialize the state for a single cpu. Usuaully this involves clearing all
registers back to their reset state. Should also hook up the fetch/store
helper functions too. */
void initialize_cpu (SIM_DESC sd, SIM_CPU *cpu)
{
struct example_sim_cpu *example_cpu = EXAMPLE_SIM_CPU (cpu);
memset (example_cpu->regs, 0, sizeof (example_cpu->regs));
example_cpu->pc = 0;
/* Make sure it's initialized outside of the 16-bit address space. */
example_cpu->sp = 0x80000;
CPU_PC_FETCH (cpu) = pc_get;
CPU_PC_STORE (cpu) = pc_set;
}
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