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Fix casting with signed/unsigned expressions 

Previously the code generator tried to infer the VHDL types. Now it
takes a much more dumb approach and forces the VHDL type to be
the same as the ivl type (derived from ivl_expr_signed and
ivl_expr_width) in the expression tree. This works much better :-)
This commit is contained in:
Nick Gasson 2008-07-08 12:58:50 +01:00
parent bd5cc96956
commit 1cd7689d03
1 changed files with 120 additions and 37 deletions
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157
tgt-vhdl/expr.cc
View File

@ -69,6 +69,39 @@ static vhdl_expr *translate_unary(ivl_expr_t e)
if (NULL == operand)
return NULL;
bool should_be_signed = ivl_expr_signed(e) != 0;
if (operand->get_type()->get_name() == VHDL_TYPE_UNSIGNED && should_be_signed) {
//operand->print();
//std::cout << "^ should be signed but is not" << std::endl;
int msb = operand->get_type()->get_msb();
int lsb = operand->get_type()->get_lsb();
vhdl_type u(VHDL_TYPE_SIGNED, msb, lsb);
operand = operand->cast(&u);
}
else if (operand->get_type()->get_name() == VHDL_TYPE_SIGNED && !should_be_signed) {
//operand->print();
//std::cout << "^ should be unsigned but is not" << std::endl;
int msb = operand->get_type()->get_msb();
int lsb = operand->get_type()->get_lsb();
vhdl_type u(VHDL_TYPE_UNSIGNED, msb, lsb);
operand = operand->cast(&u);
}
// Need to ensure that the operand is interpreted as unsigned to get VHDL
// to emulate Verilog behaviour
if (operand->get_type()->get_name() == VHDL_TYPE_SIGNED) {
int msb = operand->get_type()->get_msb();
int lsb = operand->get_type()->get_lsb();
vhdl_type u(VHDL_TYPE_UNSIGNED, msb, lsb);
operand = operand->cast(&u);
}
char opcode = ivl_expr_opcode(e);
switch (opcode) {
case '!':
@ -156,75 +189,89 @@ static vhdl_expr *translate_binary(ivl_expr_t e)
int lwidth = lhs->get_type()->get_width();
int rwidth = rhs->get_type()->get_width();
std::cout << "opwidth = " << ivl_expr_width(e)
<< " lwidth = " << lwidth
<< " rwidth = " << rwidth << std::endl;
// May need to resize the left or right hand side
/*if (lwidth < rwidth) {
lhs = lhs->cast(rhs->get_type());
}
else if (rwidth < lwidth) {
rhs = rhs->cast(lhs->get_type());
}*/
int result_width = ivl_expr_width(e);
// For === and !== we need to compare std_logic_vectors
// rather than signeds
vhdl_type std_logic_vector(VHDL_TYPE_STD_LOGIC_VECTOR, result_width-1, 0);
vhdl_type_name_t ltype = lhs->get_type()->get_name();
vhdl_type_name_t rtype = rhs->get_type()->get_name();
bool vectorop =
(lhs->get_type()->get_name() == VHDL_TYPE_SIGNED
|| lhs->get_type()->get_name() == VHDL_TYPE_UNSIGNED) &&
(rhs->get_type()->get_name() == VHDL_TYPE_SIGNED
|| rhs->get_type()->get_name() == VHDL_TYPE_UNSIGNED);
(ltype == VHDL_TYPE_SIGNED || ltype == VHDL_TYPE_UNSIGNED) &&
(rtype == VHDL_TYPE_SIGNED || rtype == VHDL_TYPE_UNSIGNED);
// May need to resize the left or right hand side
if (vectorop) {
if (lwidth < rwidth)
lhs = lhs->resize(rwidth);
else if (rwidth < lwidth)
rhs = rhs->resize(lwidth);
}
vhdl_expr *result;
switch (ivl_expr_opcode(e)) {
case '+':
return translate_numeric(lhs, rhs, VHDL_BINOP_ADD);
result = translate_numeric(lhs, rhs, VHDL_BINOP_ADD);
break;
case '-':
return translate_numeric(lhs, rhs, VHDL_BINOP_SUB);
result = translate_numeric(lhs, rhs, VHDL_BINOP_SUB);
break;
case '*':
return translate_numeric(lhs, rhs, VHDL_BINOP_MULT);
result = translate_numeric(lhs, rhs, VHDL_BINOP_MULT);
break;
case 'e':
return translate_relation(lhs, rhs, VHDL_BINOP_EQ);
result = translate_relation(lhs, rhs, VHDL_BINOP_EQ);
break;
case 'E':
if (vectorop)
return translate_relation(lhs->cast(&std_logic_vector),
result = translate_relation(lhs->cast(&std_logic_vector),
rhs->cast(&std_logic_vector), VHDL_BINOP_EQ);
else
return translate_relation(lhs, rhs, VHDL_BINOP_EQ);
result = translate_relation(lhs, rhs, VHDL_BINOP_EQ);
break;
case 'n':
return translate_relation(lhs, rhs, VHDL_BINOP_NEQ);
result = translate_relation(lhs, rhs, VHDL_BINOP_NEQ);
break;
case 'N':
if (vectorop)
return translate_relation(lhs->cast(&std_logic_vector),
result = translate_relation(lhs->cast(&std_logic_vector),
rhs->cast(&std_logic_vector), VHDL_BINOP_NEQ);
else
return translate_relation(lhs, rhs, VHDL_BINOP_NEQ);
result = translate_relation(lhs, rhs, VHDL_BINOP_NEQ);
break;
case '&': // Bitwise AND
return translate_numeric(lhs, rhs, VHDL_BINOP_AND);
result = translate_numeric(lhs, rhs, VHDL_BINOP_AND);
break;
case 'a': // Logical AND
return translate_logical(lhs, rhs, VHDL_BINOP_AND);
result = translate_logical(lhs, rhs, VHDL_BINOP_AND);
break;
case '|': // Bitwise OR
return translate_numeric(lhs, rhs, VHDL_BINOP_OR);
result = translate_numeric(lhs, rhs, VHDL_BINOP_OR);
break;
case 'o': // Logical OR
return translate_logical(lhs, rhs, VHDL_BINOP_OR);
result = translate_logical(lhs, rhs, VHDL_BINOP_OR);
break;
case '<':
return translate_relation(lhs, rhs, VHDL_BINOP_LT);
result = translate_relation(lhs, rhs, VHDL_BINOP_LT);
break;
case 'L':
return translate_relation(lhs, rhs, VHDL_BINOP_LEQ);
result = translate_relation(lhs, rhs, VHDL_BINOP_LEQ);
break;
case '>':
return translate_relation(lhs, rhs, VHDL_BINOP_GT);
result = translate_relation(lhs, rhs, VHDL_BINOP_GT);
break;
case 'G':
return translate_relation(lhs, rhs, VHDL_BINOP_GEQ);
result = translate_relation(lhs, rhs, VHDL_BINOP_GEQ);
break;
case 'l':
return translate_shift(lhs, rhs, VHDL_BINOP_SL);
result = translate_shift(lhs, rhs, VHDL_BINOP_SL);
break;
case 'r':
return translate_shift(lhs, rhs, VHDL_BINOP_SR);
result = translate_shift(lhs, rhs, VHDL_BINOP_SR);
break;
case '^':
return translate_numeric(lhs, rhs, VHDL_BINOP_XOR);
result = translate_numeric(lhs, rhs, VHDL_BINOP_XOR);
break;
default:
error("No translation for binary opcode '%c'\n",
ivl_expr_opcode(e));
@ -232,6 +279,42 @@ static vhdl_expr *translate_binary(ivl_expr_t e)
delete rhs;
return NULL;
}
if (NULL == result)
return NULL;
if (vectorop) {
bool should_be_signed = ivl_expr_signed(e) != 0;
if (result->get_type()->get_name() == VHDL_TYPE_UNSIGNED && should_be_signed) {
//result->print();
//std::cout << "^ should be signed but is not" << std::endl;
int msb = result->get_type()->get_msb();
int lsb = result->get_type()->get_lsb();
vhdl_type u(VHDL_TYPE_SIGNED, msb, lsb);
result = result->cast(&u);
}
else if (result->get_type()->get_name() == VHDL_TYPE_SIGNED && !should_be_signed) {
//result->print();
//std::cout << "^ should be unsigned but is not" << std::endl;
int msb = result->get_type()->get_msb();
int lsb = result->get_type()->get_lsb();
vhdl_type u(VHDL_TYPE_SIGNED, msb, lsb);
result = result->cast(&u);
}
int actual_width = result->get_type()->get_width();
if (actual_width != result_width) {
//result->print();
//std::cout << "^ should be " << result_width << " but is " << actual_width << std::endl;
}
}
return result;
}
static vhdl_expr *translate_select(ivl_expr_t e)