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Implemented basic real arithmetic

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This commit is contained in:
Clifford Wolf 2014-06-14 08:51:22 +02:00
parent 9dd16fa41c
commit 442a8e2875
3 changed files with 51 additions and 6 deletions
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31
frontends/ast/ast.cc
View file

@ -32,7 +32,7 @@
#include <sstream> #include <sstream>
#include <stdarg.h> #include <stdarg.h>
#include <assert.h> #include <math.h>
using namespace AST; using namespace AST;
using namespace AST_INTERNAL; using namespace AST_INTERNAL;
@ -760,6 +760,35 @@ bool AstNode::asBool()
return false; return false;
} }
int AstNode::isConst()
{
if (type == AST_CONSTANT)
return 1;
if (type == AST_REALVALUE)
return 2;
return 0;
}
double AstNode::asReal(bool is_signed)
{
if (type == AST_CONSTANT) {
RTLIL::Const val;
val.bits = bits;
double p = exp2(val.bits.size()-32);
if (val.bits.size() > 32)
val.bits.erase(val.bits.begin(), val.bits.begin()+(val.bits.size()-32));
int32_t v = val.as_int() << (32-val.bits.size());
if (is_signed)
return v * p;
return uint32_t(v) * p;
}
if (type == AST_REALVALUE)
return realvalue;
return 0;
}
// create a new AstModule from an AST_MODULE AST node // create a new AstModule from an AST_MODULE AST node
static AstModule* process_module(AstNode *ast, bool defer) static AstModule* process_module(AstNode *ast, bool defer)
{ {

4
frontends/ast/ast.h
View file

@ -240,6 +240,10 @@ namespace AST
RTLIL::Const asAttrConst(); RTLIL::Const asAttrConst();
RTLIL::Const asParaConst(); RTLIL::Const asParaConst();
bool asBool(); bool asBool();
// helper functions for real valued const eval
int isConst(); // return '1' for AST_CONSTANT and '2' for AST_REALVALUE
double asReal(bool is_signed);
}; };
// process an AST tree (ast must point to an AST_DESIGN node) and generate RTLIL code // process an AST tree (ast must point to an AST_DESIGN node) and generate RTLIL code

22
frontends/ast/simplify.cc
View file

@ -32,7 +32,7 @@
#include <sstream> #include <sstream>
#include <stdarg.h> #include <stdarg.h>
#include <assert.h> #include <math.h>
using namespace AST; using namespace AST;
using namespace AST_INTERNAL; using namespace AST_INTERNAL;
@ -1433,10 +1433,22 @@ skip_dynamic_range_lvalue_expansion:;
if (0) { case AST_MUL: const_func = RTLIL::const_mul; } if (0) { case AST_MUL: const_func = RTLIL::const_mul; }
if (0) { case AST_DIV: const_func = RTLIL::const_div; } if (0) { case AST_DIV: const_func = RTLIL::const_div; }
if (0) { case AST_MOD: const_func = RTLIL::const_mod; } if (0) { case AST_MOD: const_func = RTLIL::const_mod; }
if (children[0]->type == AST_CONSTANT && children[1]->type == AST_CONSTANT) { if (children[0]->isConst() && children[1]->isConst()) {
RTLIL::Const y = const_func(children[0]->bitsAsConst(width_hint, sign_hint), if (children[0]->isConst() + children[1]->isConst() > 2) {
children[1]->bitsAsConst(width_hint, sign_hint), sign_hint, sign_hint, width_hint); newNode = new AstNode(AST_REALVALUE);
newNode = mkconst_bits(y.bits, sign_hint); switch (type) {
case AST_ADD: newNode->realvalue = children[0]->asReal(sign_hint) + children[1]->asReal(sign_hint); break;
case AST_SUB: newNode->realvalue = children[0]->asReal(sign_hint) - children[1]->asReal(sign_hint); break;
case AST_MUL: newNode->realvalue = children[0]->asReal(sign_hint) * children[1]->asReal(sign_hint); break;
case AST_DIV: newNode->realvalue = children[0]->asReal(sign_hint) / children[1]->asReal(sign_hint); break;
case AST_MOD: newNode->realvalue = fmod(children[0]->asReal(sign_hint), children[1]->asReal(sign_hint)); break;
default: log_abort();
}
} else {
RTLIL::Const y = const_func(children[0]->bitsAsConst(width_hint, sign_hint),
children[1]->bitsAsConst(width_hint, sign_hint), sign_hint, sign_hint, width_hint);
newNode = mkconst_bits(y.bits, sign_hint);
}
} }
break; break;
if (0) { case AST_POS: const_func = RTLIL::const_pos; } if (0) { case AST_POS: const_func = RTLIL::const_pos; }