RFA: RL78: Fix simulation of G13 multiply/divide peripheral

RFA: RL78: Fix simulation of G13 multiply/divide peripheral

[Nick Clifton]

Hi DJ,

  The patch below fixes a problem with the RL78 simulator simulation of
  the G13 multiply/divide peripheral.  Namely the MDB register is not
  32-bit aligned so the mem_put_si and mem_get_si functions cannot be
  used with it.  Instead the value has to be split up into two 16-bit
  parts and the mem_{get|put}_hi functions used.

  In addition the patch adds support for the new G13 and G14 flags in
  RL78 ELF headers.  If one of these flag bits is present then the patch
  selects the appropriate G10/G13/G14 emulation mode.

  Tested with no regressions on an rl78-elf toolchain.

  OK to apply ?

Cheers
  Nick

sim/rl78/ChangeLog
2015-03-19  Nick Clifton  <nickc@redhat.com>

	* load.c (rl78_load): If the G10, G13 or G14 flag bits are set in
	the ELF header use them to select the proper emulation mode.
	* mem.c (mem_put_byte): Use mem_put_hi to store a value into the
	MDB register.
	(mem_get_byte): Use mem_get_hi to extract a value from the MDB
	register.

diff --git a/sim/rl78/load.c b/sim/rl78/load.c
index fcbe1ae..8d3a138 100644
--- a/sim/rl78/load.c
+++ b/sim/rl78/load.c
@@ -27,6 +27,8 @@
 
 #include "libiberty.h"
 #include "bfd.h"
+#include "elf-bfd.h"
+#include "elf/rl78.h"
 #include "libbfd.h"
 #include "cpu.h"
 #include "mem.h"
@@ -89,7 +91,17 @@ rl78_load (bfd *prog, host_callback *callbacks, const char * const simname)
       fprintf (stderr, "%s: Failed to read program headers\n", simname);
       return;
     }
-  
+
+  rl78_g10_mode = 0;
+  switch (elf_elfheader (prog)->e_flags & E_FLAG_RL78_CPU_MASK)
+    {
+    case E_FLAG_RL78_G10: rl78_g10_mode = 1; break;
+    case E_FLAG_RL78_G13: g13_multiply = 1; break;
+    case E_FLAG_RL78_G14:
+    default:
+      break;
+    }  
+
   for (i = 0; i < num_headers; i++)
     {
       Elf_Internal_Phdr * p = phdrs + i;
diff --git a/sim/rl78/mem.c b/sim/rl78/mem.c
index 042c76e..8d95199 100644
--- a/sim/rl78/mem.c
+++ b/sim/rl78/mem.c
@@ -140,6 +140,10 @@ mem_put_byte (int address, unsigned char value)
       printf ("Warning: SP value 0x%04x truncated at pc=0x%05x\n", value, pc);
       value &= ~1;
     }
+
+  if (! g13_multiply)
+    return;
+
   if (address == MDUC)
     {
       if ((value & 0x81) == 0x81)
@@ -166,20 +170,23 @@ mem_put_byte (int address, unsigned char value)
 	      ahu = mem_get_hi (MDAH);
 	      rvu = alu * ahu;
 	      tprintf  ("MDUC: %lu * %lu = %lu\n", alu, ahu, rvu);
-	      mem_put_si (MDBL, rvu);
+	      mem_put_hi (MDBL, rvu & 0xffff);
+	      mem_put_hi (MDBH, rvu >> 16);
 	      break;
 	    case 0x08:
 	      als = sign_ext (mem_get_hi (MDAL), 16);
 	      ahs = sign_ext (mem_get_hi (MDAH), 16);
 	      rvs = als * ahs;
 	      tprintf  ("MDUC: %ld * %ld = %ld\n", als, ahs, rvs);
-	      mem_put_si (MDBL, rvs);
+	      mem_put_hi (MDBL, rvs & 0xffff);
+	      mem_put_hi (MDBH, rvs >> 16);
 	      break;
 	    case 0x40:
 	      alu = mem_get_hi (MDAL);
 	      ahu = mem_get_hi (MDAH);
 	      rvu = alu * ahu;
-	      mem_put_si (MDBL, rvu);
+	      mem_put_hi (MDBL, rvu & 0xffff);
+	      mem_put_hi (MDBH, rvu >> 16);
 	      mdc = mem_get_si (MDCL);
 	      tprintf  ("MDUC: %lu * %lu + %lu = ", alu, ahu, mdc);
 	      mdc += (long) rvu;
@@ -190,7 +197,8 @@ mem_put_byte (int address, unsigned char value)
 	      als = sign_ext (mem_get_hi (MDAL), 16);
 	      ahs = sign_ext (mem_get_hi (MDAH), 16);
 	      rvs = als * ahs;
-	      mem_put_si (MDBL, rvs);
+	      mem_put_hi (MDBL, rvs & 0xffff);
+	      mem_put_hi (MDBH, rvs >> 16);
 	      mdc = mem_get_si (MDCL);
 	      tprintf  ("MDUC: %ld * %ld + %ld = ", als, ahs, mdc);
 	      tprintf ("%ld\n", mdc);
@@ -228,7 +236,7 @@ mem_get_byte (int address)
 	    unsigned long a, b, q, r;
 	    memory [MDUC] &= 0xfe;
 	    a = mem_get_si (MDAL);
-	    b = mem_get_si (MDAL);
+	    b = mem_get_hi (MDBL) | (mem_get_hi (MDBH) << 16);
 	    if (b == 0)
 	      {
 		q = ~0;

Re: RFA: RL78: Fix simulation of G13 multiply/divide peripheral

[DJ Delorie]

Ok.

Re: RFA: RL78: Fix simulation of G13 multiply/divide peripheral

[Mike Frysinger]

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On 19 Mar 2015 15:51, Nick Clifton wrote:
>   The patch below fixes a problem with the RL78 simulator simulation of
>   the G13 multiply/divide peripheral.  Namely the MDB register is not
>   32-bit aligned so the mem_put_si and mem_get_si functions cannot be
>   used with it.  Instead the value has to be split up into two 16-bit
>   parts and the mem_{get|put}_hi functions used.
> 
>   In addition the patch adds support for the new G13 and G14 flags in
>   RL78 ELF headers.  If one of these flag bits is present then the patch
>   selects the appropriate G10/G13/G14 emulation mode.
> 
>   Tested with no regressions on an rl78-elf toolchain.

how do you really know when there are no sim tests ?
-mike

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Re: RFA: RL78: Fix simulation of G13 multiply/divide peripheral

[Nicholas Clifton]

Hi Mike,

>>    Tested with no regressions on an rl78-elf toolchain.
>
> how do you really know when there are no sim tests ?

Because I use the sim to help run the gcc testsuite, and without this 
patch several gcc tests were failing due to errors from the sim about 
misaligned accesses to the MDB register.  With this patch those failures 
went away and no new failures were introduced.  Hence I felt confident 
that the patch was good.

Cheers
   Nick

Re: RFA: RL78: Fix simulation of G13 multiply/divide peripheral

[Mike Frysinger]

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On 20 Mar 2015 10:28, Nicholas Clifton wrote:
> >>    Tested with no regressions on an rl78-elf toolchain.
> >
> > how do you really know when there are no sim tests ?
> 
> Because I use the sim to help run the gcc testsuite, and without this 
> patch several gcc tests were failing due to errors from the sim about 
> misaligned accesses to the MDB register.  With this patch those failures 
> went away and no new failures were introduced.  Hence I felt confident 
> that the patch was good.

OK.  it would be nice if there were at least one minor sim test though.
it's dirt simple to add one written in just assembly ...

i have found directed sim tests to be better than gcc in the long run.
-mike

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Re: RFA: RL78: Fix simulation of G13 multiply/divide peripheral

[Mike Frysinger]

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On 19 Mar 2015 15:51, Nick Clifton wrote:
>   The patch below fixes a problem with the RL78 simulator simulation of
>   the G13 multiply/divide peripheral.  Namely the MDB register is not
>   32-bit aligned so the mem_put_si and mem_get_si functions cannot be
>   used with it.  Instead the value has to be split up into two 16-bit
>   parts and the mem_{get|put}_hi functions used.
> 
>   In addition the patch adds support for the new G13 and G14 flags in
>   RL78 ELF headers.  If one of these flag bits is present then the patch
>   selects the appropriate G10/G13/G14 emulation mode.

did you forgot to commit some other change ?  rl78 fails to build now:

gcc -DHAVE_CONFIG_H     -DPROFILE=1 -DWITH_PROFILE=-1          
-DDEFAULT_INLINE=0           -Wall   -I. -I../../../../sim/rl78 -I../common 
-I../../../../sim/rl78/../common -I../../include 
-I../../../../sim/rl78/../../include -I../../bfd 
-I../../../../sim/rl78/../../bfd -I../../opcodes 
-I../../../../sim/rl78/../../opcodes  -g -O2 -c -o load.o -MT load.o -MMD -MP 
-MF .deps/load.Tpo ../../../../sim/rl78/load.c
../../../../sim/rl78/load.c: In function 'rl78_load':
../../../../sim/rl78/load.c:95:3: error: 'rl78_g10_mode' undeclared (first use 
in this function)
   rl78_g10_mode = 0;
   ^
../../../../sim/rl78/load.c:95:3: note: each undeclared identifier is reported 
only once for each function it appears in
../../../../sim/rl78/load.c:99:16: error: 'g13_multiply' undeclared (first use 
in this function)
     case E_FLAG_RL78_G13: g13_multiply = 1; break;
                ^
Makefile:530: recipe for target 'load.o' failed
make[2]: *** [load.o] Error 1

i don't see either of those identifiers in the current master.
-mike

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Re: RFA: RL78: Fix simulation of G13 multiply/divide peripheral

[Nicholas Clifton]

Hi Mike,

> did you forgot to commit some other change ?  rl78 fails to build now:

> ../../../../sim/rl78/load.c:95:3: error: 'rl78_g10_mode' undeclared (first use
> in this function)

*doh*.  Yes I did.  Sorry about that.  Fixed with this patch:

Cheers
   Nick

sim/rl78/ChangeLog
2015-03-23  Nick Clifton  <nickc@redhat.com>

	* cpu.c (rl78_g10_mode): Declare.
	(g13_multiply): Declare.
	* cpu.h (rl78_g10_mode): Export.
	(g13_multiply): Export.

diff --git a/sim/rl78/cpu.c b/sim/rl78/cpu.c
index a5056fc..32b1399 100644
--- a/sim/rl78/cpu.c
+++ b/sim/rl78/cpu.c
@@ -32,6 +32,8 @@ int verbose = 0;
  int trace = 0;
  int rl78_in_gdb = 1;
  int timer_enabled = 2;
+int rl78_g10_mode = 0;
+int g13_multiply = 0;

  #define REGISTER_ADDRESS 0xffee0

diff --git a/sim/rl78/cpu.h b/sim/rl78/cpu.h
index e2457bb..0e10db9 100644
--- a/sim/rl78/cpu.h
+++ b/sim/rl78/cpu.h
@@ -97,4 +97,7 @@ extern int timer_enabled;
  extern void dump_counts_per_insn (const char * filename);
  extern unsigned int counts_per_insn[0x100000];

+extern int rl78_g10_mode;
+extern int g13_multiply;
+
  #endif