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V0.8: Fail if both an LPM/wire and a reg drive a nexus. 

In synthesis we transform registers into wires, but if there is bad
Verilog code where the register is written from non-synthesized code
then we can't do this! This patch adds a check in the code generator
for this and prints a error message instead of generating a .resolv
to combine the two, which is certainly not correct.
This commit is contained in:
Cary R 2010-12-23 18:34:54 -08:00 committed by Stephen Williams
parent 34661e9af5
commit 14926e7ce0
1 changed files with 39 additions and 1 deletions
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40
tgt-vvp/vvp_scope.c
View File

@ -489,6 +489,7 @@ const char* draw_net_input(ivl_nexus_t nex)
unsigned ndrivers = 0;
static ivl_nexus_ptr_t *drivers = 0x0;
static unsigned adrivers = 0;
ivl_signal_type_t ntype = IVL_SIT_NONE;
const char*resolv_type;
@ -534,15 +535,52 @@ const char* draw_net_input(ivl_nexus_t nex)
break;
}
for (idx = 0 ; idx < ivl_nexus_ptrs(nex) ; idx += 1) {
ivl_nexus_ptr_t nptr = ivl_nexus_ptr(nex, idx);
ivl_signal_t nsig = ivl_nexus_ptr_sig(nptr);
ivl_lpm_t nlpm = ivl_nexus_ptr_lpm(nptr);
/* Skip input only pins. */
if ((ivl_nexus_ptr_drive0(nptr) == IVL_DR_HiZ)
&& (ivl_nexus_ptr_drive1(nptr) == IVL_DR_HiZ))
continue;
/* Check that both an LPM and a reg are not driving a net. */
if (nlpm) {
if (ntype != IVL_SIT_REG) {
ntype = IVL_SIT_TRI;
} else {
fprintf(stderr, "vvp.tgt: error: Found a net driven by "
"both a reg and an lpm (wire)!\n");
fprintf(stderr, " : This may be caused by "
"invalid Verilog code (e.g. "
"assigning \n");
fprintf(stderr, " : to a synthesized net "
"from non-synthesized code).\n");
fprintf(stderr, " : C source file %s:%u\n",
__FILE__, __LINE__);
exit(1);
}
}
if (nsig) {
ivl_signal_type_t stype = ivl_signal_type(nsig);
if (ntype == IVL_SIT_NONE) {
ntype = stype;
} else if ((ntype == IVL_SIT_REG || stype == IVL_SIT_REG) &&
(ntype != stype)) {
fprintf(stderr, "vvp.tgt: error: Found a net driven by "
"both a reg and a wire (lpm?)!\n");
fprintf(stderr, " : This may be caused by "
"invalid Verilog code (e.g. "
"assigning \n");
fprintf(stderr, " : to a synthesized net "
"from non-synthesized code).\n");
fprintf(stderr, " : C source file %s:%u\n",
__FILE__, __LINE__);
exit(1);
}
}
/* Save this driver. */
if (ndrivers >= adrivers) {
adrivers += 4;