[PATCH 2/2] [pr gdb/19447] sim: mips: Add shadow mappings for 32-bit memory address space

[Faraz Shahbazker <fshahbazker@wavecomp.com>]

32-bit MIPS programs run on the 64-bit simulator model in 64-bit
sign-extended space. The mapping from 64-bit sign-extended addresses to
32-bit addresses was removed by commit
26f8bf63bf36f9062a5cc1afacf71462a4abe0c8, breaking the 64-bit simulator
model. Add shadow mappings from 64-bit sign extended address space to
32-bit address spaces, in lieu of the AddressTranslation function.

2021-05-04  Faraz Shahbazker  <fshahbazker@wavecomp.com>

sim/mips/ChangeLog:
	* interp.c (sim_open): Add shadow mappings from 32-bit
	address space to 64-bit sign-extended address space.
---
 sim/mips/ChangeLog |  5 +++++
 sim/mips/interp.c  | 12 ++++++++++--
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/sim/mips/ChangeLog b/sim/mips/ChangeLog
index 5dd0dc8512f..db88d64852e 100644
--- a/sim/mips/ChangeLog
+++ b/sim/mips/ChangeLog
@@ -1,3 +1,8 @@
+2021-05-04  Faraz Shahbazker  <fshahbazker@wavecomp.com>
+
+	* interp.c (sim_open): Add memory aliases from 64-bit
+	 sign-extended address space to 32-bit address space.
+
 2021-05-04  Faraz Shahbazker  <fshahbazker@wavecomp.com>
 
 	* interp.c (sim_create_inferior): Only truncate sign extension
diff --git a/sim/mips/interp.c b/sim/mips/interp.c
index fc3a953f3b9..e190a00ff38 100644
--- a/sim/mips/interp.c
+++ b/sim/mips/interp.c
@@ -438,6 +438,9 @@ sim_open (SIM_OPEN_KIND kind, host_callback *cb,
 	  /* memory alias K1BASE@1,K1SIZE%MEMSIZE,K0BASE */
 	  sim_do_commandf (sd, "memory alias 0x%lx@1,0x%lx%%0x%lx,0x%0x",
 			   K1BASE, K1SIZE, (long)mem_size, K0BASE);
+	  if (WITH_TARGET_WORD_BITSIZE == 64)
+	    sim_do_commandf (sd, "memory alias 0x%lx,0x%lx,0x%lx",
+			     (K0BASE), (long)mem_size, EXTENDED(K0BASE));
 	}
 
       device_init(sd);
@@ -699,8 +702,13 @@ sim_open (SIM_OPEN_KIND kind, host_callback *cb,
       unsigned idt_monitor_size = 1 << 11;
 
       /* the default monitor region */
-      sim_do_commandf (sd, "memory region 0x%x,0x%x",
-		       idt_monitor_base, idt_monitor_size);
+      if (WITH_TARGET_WORD_BITSIZE == 64)
+	sim_do_commandf (sd, "memory alias 0x%lx,0x%lx,0x%lx",
+			 (idt_monitor_base), (long)idt_monitor_size,
+			 EXTENDED (idt_monitor_base));
+      else
+	sim_do_commandf (sd, "memory region 0x%lx,0x%x",
+			 idt_monitor_base, idt_monitor_size);
 
       /* Entry into the IDT monitor is via fixed address vectors, and
 	 not using machine instructions. To avoid clashing with use of
-- 
2.25.1