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Diffstat (limited to 'cortex-m-rt/asm.s')
| -rw-r--r-- | cortex-m-rt/asm.s | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/cortex-m-rt/asm.s b/cortex-m-rt/asm.s index 50a3fa5..1be4a02 100644 --- a/cortex-m-rt/asm.s +++ b/cortex-m-rt/asm.s @@ -17,3 +17,26 @@ HardFaultTrampoline: 0: mrs r0, PSP b HardFault + + .section .text.FpuTrampoline, "ax" + .global FpuTrampoline + # .type and .thumb_func are both required; otherwise its Thumb bit does not + # get set and an invalid vector table is generated + .type FpuTrampoline,%function + .thumb_func + # This enables the FPU and jumps to the main function. +FpuTrampoline: + # Address of SCB.CPACR. + ldr r0, =0xE000ED88 + # Enable access to CP10 and CP11 from both privileged and unprivileged mode. + ldr r1, =(0b1111 << 20) + # RMW. + ldr r2, [r0] + orr r2, r2, r1 + str r2, [r0] + # Barrier is required on some processors. + dsb + isb + # Hand execution over to `main`. + bl main + # Note: `main` must not return. `bl` is used only because it has a wider range than `b`. |