sw: Fix start snich bootstrap code

sw/snRuntime/src/platforms/rtl/start_snitch.S.in

@@ -0,0 +1,57 @@
+# Copyright 2020 ETH Zurich and University of Bologna.
+# Licensed under the Apache License, Version 2.0, see LICENSE for details.
+# SPDX-License-Identifier: Apache-2.0
+
+#include "../shared/start_snitch.S"
+
+#include <spatz_cluster_peripheral.h>
+
+//.global BOOTDATA
+
+# Function to terminate execution.
+#
+# Expecting:
+# - a0: exit code
+# - a1: device tree ptr
+_snrt_exit:
+    .globl _snrt_exit
+    # Determine global core index.
+    addi      sp, sp, -8
+    sw        a0, 0(sp)
+    sw        ra, 4(sp)
+    call      snrt_global_core_idx
+    # reload exit code into t0
+    lw        t0, 0(sp)
+    lw        ra, 4(sp)
+    addi      sp, sp, 8
+
+    # Only first core triggers exit.
+    # - a0: global core index
+    # - t0: exit code
+    bnez      a0, 1f
+    slli      t0, t0, 1
+    ori       t0, t0, 1
+
+    # Load the start address and size of the TCDM
+    li         t1, @MEM_TCDM_ORIGIN@
+    li         t2, @MEM_TCDM_SIZE@
+
+    # Final address of the TCDM
+    add     t1, t1, t2
+
+    # Address of the EOC register
+    addi     t1, t1, SPATZ_CLUSTER_PERIPHERAL_CLUSTER_EOC_EXIT_REG_OFFSET
+
+    # Return to EOC register
+    sw         t0, 0(t1)
+
+    # Return to HTIF
+    la        t1, tohost
+    sw        t0, 0(t1)
+1:  ret
+
+# HTIF sections
+.pushsection .htif,"aw",@progbits;
+.align 6; .global tohost; tohost: .dword 0;
+.align 6; .global fromhost; fromhost: .dword 0;
+

sw/snRuntime/src/platforms/standalone/start_snitch.S

@@ -4,10 +4,6 @@
 
 #include "../shared/start_snitch.S"
 
-#include <spatz_cluster_peripheral.h>
-
-//.global BOOTDATA
-
 # Function to terminate execution.
 #
 # Expecting:
@@ -31,21 +27,6 @@ _snrt_exit:
     bnez      a0, 1f
     slli      t0, t0, 1
     ori       t0, t0, 1
-
-    # Load the start address and size of the TCDM
-    li         t1, @MEM_TCDM_ORIGIN@
-    li         t2, @MEM_TCDM_SIZE@
-
-    # Final address of the TCDM
-    add     t1, t1, t2
-
-    # Address of the EOC register
-    addi     t1, t1, SPATZ_CLUSTER_PERIPHERAL_CLUSTER_EOC_EXIT_REG_OFFSET
-
-    # Return to EOC register
-    sw         t0, 0(t1)
-
-    # Return to HTIF
     la        t1, tohost
     sw        t0, 0(t1)
 1:  ret