rust-embedded
diff --git a/‎cortex-m-rt/asm.s
Lines changed: 6 additions & 2 deletions b/‎cortex-m-rt/asm.s
Lines changed: 6 additions & 2 deletions
diff --git a/‎cortex-m-rt/bin/thumbv6m-none-eabi.a
4 Bytes b/‎cortex-m-rt/bin/thumbv6m-none-eabi.a
4 Bytes
diff --git a/‎cortex-m-rt/bin/thumbv7em-none-eabi.a
4 Bytes b/‎cortex-m-rt/bin/thumbv7em-none-eabi.a
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diff --git a/‎cortex-m-rt/bin/thumbv7em-none-eabihf.a
4 Bytes b/‎cortex-m-rt/bin/thumbv7em-none-eabihf.a
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diff --git a/‎cortex-m-rt/bin/thumbv7m-none-eabi.a
4 Bytes b/‎cortex-m-rt/bin/thumbv7m-none-eabi.a
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diff --git a/‎cortex-m-rt/bin/thumbv8m.base-none-eabi.a
4 Bytes b/‎cortex-m-rt/bin/thumbv8m.base-none-eabi.a
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diff --git a/‎cortex-m-rt/bin/thumbv8m.main-none-eabi.a
4 Bytes b/‎cortex-m-rt/bin/thumbv8m.main-none-eabi.a
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diff --git a/‎cortex-m-rt/bin/thumbv8m.main-none-eabihf.a
4 Bytes b/‎cortex-m-rt/bin/thumbv8m.main-none-eabihf.a
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@@ -60,12 +60,16 @@ FpuTrampoline:
   .cfi_startproc
 PreResetTrampoline:
   # set LR to the initial value used by the ARMv7-M (0xFFFF_FFFF)
-  ldr r0,=0xffffffff
-  mov lr,r0
+  ldr r4,=0xffffffff
+  mov lr,r4
 
   # run the pre-init code
   bl __pre_init
 
+  # the call above clobbers LR, but tools may expect LR to be 0xFFFFFFFF when reaching the first
+  # call frame, so we restore it to its previous value (r4 is preserved by subroutines)
+  mov lr,r4
+
   # initialize .data and .bss memory
   ldr r0,=__sbss
   ldr r1,=__ebss