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Implement comparison operators

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This commit is contained in:
Eugen Wissner 2024-04-02 09:07:13 +02:00
parent 3c19bf1504
commit 4251c361c7
Signed by: belka
GPG Key ID: A27FDC1E8EE902C0
9 changed files with 205 additions and 42 deletions
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2
TODO
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@ -15,6 +15,8 @@
- It seems instructions are correctly encoded only if the compiler is running
on a little endian architecture.
- Merge declaration and definition nodes.
- Pointer.
- Static array.
# Shell
- Persist the history.

46
backend/riscv.cpp
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@ -235,11 +235,13 @@ namespace elna::riscv
void visitor::visit(source::call_statement *statement)
{
std::size_t argument_offset{ 0 };
for (auto& argument : statement->arguments())
{
argument->accept(this);
const auto free_register = this->register_in_use ? x_register::a0 : x_register::t0;
this->instructions.push_back(instruction(base_opcode::store)
.s(argument_offset, funct3_t::sw, x_register::sp, x_register::a0));
.s(argument_offset, funct3_t::sw, x_register::sp, free_register));
argument_offset += 4;
}
relocate(statement->name(), address_t::text);
@ -321,19 +323,21 @@ namespace elna::riscv
this->register_in_use = true;
expression->lhs().accept(this);
auto lhs_stack_position = this->variable_counter * 4;
++this->variable_counter;
this->instructions.push_back( // movl %eax, -x(%rbp); where x is a number.
this->instructions.push_back(
instruction(base_opcode::store)
.s(static_cast<std::uint32_t>(this->variable_counter * 4), funct3_t::sw, x_register::sp, x_register::a0)
.s(static_cast<std::uint32_t>(lhs_stack_position), funct3_t::sw, x_register::sp, x_register::a0)
);
auto lhs_stack_position = ++this->variable_counter;
this->register_in_use = false;
expression->rhs().accept(this);
this->register_in_use = lhs_register == x_register::a0; // Restore.
this->instructions.push_back(instruction(base_opcode::load)
.i(x_register::a0, funct3_t::lw, x_register::sp,
static_cast<std::int8_t>((lhs_stack_position - 1) * 4))
static_cast<std::int8_t>(lhs_stack_position))
);
// Calculate the result and assign it to a variable on the stack.
@ -355,6 +359,38 @@ namespace elna::riscv
this->instructions.push_back(instruction(base_opcode::op)
.r(lhs_register, funct3_t::div, x_register::a0, x_register::t0, funct7_t::muldiv));
break;
case source::binary_operator::equals:
this->instructions.push_back(instruction(base_opcode::op)
.r(lhs_register, funct3_t::sub, x_register::a0, x_register::t0, funct7_t::sub));
this->instructions.push_back(instruction(base_opcode::opImm)
.i(lhs_register, funct3_t::sltiu, lhs_register, 1));
break;
case source::binary_operator::not_equals:
this->instructions.push_back(instruction(base_opcode::op)
.r(lhs_register, funct3_t::sub, x_register::a0, x_register::t0, funct7_t::sub));
this->instructions.push_back(instruction(base_opcode::op)
.r(lhs_register, funct3_t::sltu, x_register::zero, lhs_register));
break;
case source::binary_operator::less:
this->instructions.push_back(instruction(base_opcode::op)
.r(lhs_register, funct3_t::sltu, x_register::a0, x_register::t0));
break;
case source::binary_operator::greater_equal:
this->instructions.push_back(instruction(base_opcode::op)
.r(lhs_register, funct3_t::sltu, x_register::t0, x_register::a0));
break;
case source::binary_operator::greater:
this->instructions.push_back(instruction(base_opcode::op)
.r(lhs_register, funct3_t::slt, x_register::a0, x_register::t0));
this->instructions.push_back(instruction(base_opcode::opImm)
.i(lhs_register, funct3_t::xori, lhs_register, 1));
break;
case source::binary_operator::less_equal:
this->instructions.push_back(instruction(base_opcode::op)
.r(lhs_register, funct3_t::slt, x_register::t0, x_register::a0));
this->instructions.push_back(instruction(base_opcode::opImm)
.i(lhs_register, funct3_t::xori, lhs_register, 1));
break;
}
}

3
include/elna/backend/riscv.hpp
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@ -146,7 +146,8 @@ namespace elna::riscv
instruction& i(x_register rd, funct3_t funct3, x_register rs1, std::uint32_t immediate);
instruction& s(std::uint32_t imm, funct3_t funct3, x_register rs1, x_register rs2);
instruction& b(std::uint32_t imm, funct3_t funct3, x_register rs1, x_register rs2);
instruction& r(x_register rd, funct3_t funct3, x_register rs1, x_register rs2, funct7_t funct7 = funct7_t::none);
instruction& r(x_register rd, funct3_t funct3, x_register rs1, x_register rs2,
funct7_t funct7 = funct7_t::none);
instruction& u(x_register rd, std::uint32_t imm);
instruction& j(x_register rd, std::uint32_t imm);

5
include/elna/source/lexer.hpp
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@ -73,9 +73,10 @@ namespace elna::source
colon,
when,
then,
_while,
loop,
_do,
procedure
procedure,
comparison_operator
};
/**

9
include/elna/source/parser.hpp
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@ -11,7 +11,13 @@ namespace elna::source
sum,
subtraction,
multiplication,
division
division,
equals,
not_equals,
less,
greater,
less_equal,
greater_equal
};
class declaration;
@ -280,6 +286,7 @@ namespace elna::source
std::unique_ptr<expression> parse_factor();
std::unique_ptr<expression> parse_term();
std::unique_ptr<expression> parse_expression();
std::unique_ptr<expression> parse_condition();
std::unique_ptr<constant_definition> parse_constant_definition();
std::unique_ptr<procedure_definition> parse_procedure_definition();
std::unique_ptr<declaration> parse_declaration();

46
source/lexer.cpp
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@ -204,7 +204,8 @@ namespace elna::source
{
return of() == type::identifier
|| of() == type::term_operator
|| of() == type::factor_operator;
|| of() == type::factor_operator
|| of() == type::comparison_operator;
}
bool token::is_numeric() const noexcept
@ -257,12 +258,14 @@ namespace elna::source
return "«if»";
case type::then:
return "«then»";
case type::_while:
case type::loop:
return "«while»";
case type::_do:
return "«do»";
case type::procedure:
return "«proc»";
case type::comparison_operator:
return "«comparison_operator»";
};
assert(false);
}
@ -446,7 +449,7 @@ namespace elna::source
}
else if (word == "while")
{
tokens.emplace_back(token::type::_while, iterator.position());
tokens.emplace_back(token::type::loop, iterator.position());
}
else if (word == "do")
{
@ -477,12 +480,49 @@ namespace elna::source
tokens.emplace_back(token::type::term_operator, _operator.c_str(), iterator.position());
}
else if (*iterator == '/' && iterator + 1 != text_end && *(iterator + 1) == '=')
{
tokens.emplace_back(token::type::comparison_operator, "n", iterator.position());
++iterator;
}
else if (*iterator == '*' || *iterator == '/')
{
std::string _operator{ *iterator };
tokens.emplace_back(token::type::factor_operator, _operator.c_str(), iterator.position());
}
else if (*iterator == '<')
{
std::string _operator;
auto operator_position = iterator.position();
if (iterator + 1 == text_end || *(iterator + 1) != '=')
{
_operator.push_back(*iterator);
}
else
{
++iterator;
_operator.push_back('l');
}
tokens.emplace_back(token::type::comparison_operator, _operator.c_str(), operator_position);
}
else if (*iterator == '>')
{
std::string _operator;
auto operator_position = iterator.position();
if (iterator + 1 == text_end || *(iterator + 1) != '=')
{
_operator.push_back(*iterator);
}
else
{
++iterator;
_operator.push_back('g');
}
tokens.emplace_back(token::type::comparison_operator, _operator.c_str(), operator_position);
}
else if (*iterator == ':' && iterator + 1 != text_end && *(iterator + 1) == '=')
{
tokens.emplace_back(token::type::assignment, iterator.position());

64
source/parser.cpp
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@ -262,6 +262,24 @@ namespace elna::source
case '/':
this->m_operator = binary_operator::division;
break;
case '=':
this->m_operator = binary_operator::equals;
break;
case 'n':
this->m_operator = binary_operator::not_equals;
break;
case '<':
this->m_operator = binary_operator::less;
break;
case 'l':
this->m_operator = binary_operator::less_equal;
break;
case '>':
this->m_operator = binary_operator::greater;
break;
case 'g':
this->m_operator = binary_operator::greater_equal;
break;
default:
throw std::logic_error("Invalid binary operator");
}
@ -442,7 +460,7 @@ namespace elna::source
{
++iterator;
auto expression = parse_expression();
auto expression = parse_condition();
++iterator;
@ -489,6 +507,38 @@ namespace elna::source
return term;
}
std::unique_ptr<expression> parser::parse_condition()
{
std::unique_ptr<expression> lhs;
if ((lhs = parse_expression()) == nullptr)
{
return lhs;
}
unsigned char _operator{ 0 };
if (iterator.current().of() == source::token::type::equals)
{
_operator = '=';
}
else if (iterator.current().of() == source::token::type::comparison_operator)
{
_operator = iterator->identifier()[0];
}
else
{
return lhs;
}
++iterator;
auto rhs = parse_expression();
if (rhs == nullptr)
{
return nullptr;
}
return std::make_unique<binary_expression>(std::move(lhs), std::move(rhs), _operator);
}
std::unique_ptr<constant_definition> parser::parse_constant_definition()
{
auto definition_identifier = iterator.advance(token::type::identifier);
@ -595,7 +645,7 @@ namespace elna::source
{
return parse_if_statement();
}
else if (iterator.current(token::type::_while))
else if (iterator.current(token::type::loop))
{
return parse_while_statement();
}
@ -618,7 +668,7 @@ namespace elna::source
++iterator;
return call;
}
while ((argument_expression = parse_expression()) != nullptr)
while ((argument_expression = parse_condition()) != nullptr)
{
call->arguments().push_back(std::move(argument_expression));
@ -674,7 +724,7 @@ namespace elna::source
{
return nullptr;
}
auto rvalue = parse_expression();
auto rvalue = parse_condition();
if (rvalue == nullptr)
{
@ -689,7 +739,7 @@ namespace elna::source
{
return nullptr;
}
auto condition = parse_expression();
auto condition = parse_condition();
if (condition == nullptr || !iterator.skip(token::type::then))
{
@ -706,11 +756,11 @@ namespace elna::source
std::unique_ptr<while_statement> parser::parse_while_statement()
{
if (!iterator.skip(token::type::_while))
if (!iterator.skip(token::type::loop))
{
return nullptr;
}
auto condition = parse_expression();
auto condition = parse_condition();
if (condition == nullptr || !iterator.skip(token::type::_do))
{

12
tests/expectations/print_equals.txt Normal file
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@ -0,0 +1,12 @@
t
f
t
f
f
t
t
f
t
f
f
t

14
tests/print_equals.eln Normal file
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@ -0,0 +1,14 @@
begin
writeb(5 = 5);
writeb(5 = 4);
writeb(5 /= 4);
writeb(5 /= 5);
writeb(5 < 4);
writeb(4 < 5);
writeb(5 >= 4);
writeb(4 >= 5);
writeb(5 > 4);
writeb(4 > 5);
writeb(5 <= 4);
writeb(4 <= 5)
end.