152 lines
2.9 KiB
ArmAsm
152 lines
2.9 KiB
ArmAsm
#if __riscv_xlen == 64
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# define STORE sd
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# define LOAD ld
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# define LOG_REGBYTES 3
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#else
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# define STORE sw
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# define LOAD lw
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# define LOG_REGBYTES 2
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#endif
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#define REGBYTES (1 << LOG_REGBYTES)
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/*
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Entry point of all programs (_start).
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It initializes DWARF call frame information, the stack pointer, the
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frame pointer (needed for closures to work in start_rust) and the global
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pointer. Then it calls _start_rust.
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*/
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.section .text.init, "ax"
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.global _start
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_start:
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.cfi_startproc
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.cfi_undefined ra
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csrw mie, 0
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csrw mip, 0
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li x1, 0
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li x2, 0
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li x3, 0
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li x4, 0
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li x5, 0
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li x6, 0
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li x7, 0
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li x8, 0
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li x9, 0
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li x10,0
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li x11,0
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li x12,0
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li x13,0
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li x14,0
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li x15,0
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li x16,0
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li x17,0
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li x18,0
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li x19,0
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li x20,0
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li x21,0
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li x22,0
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li x23,0
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li x24,0
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li x25,0
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li x26,0
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li x27,0
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li x28,0
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li x29,0
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li x30,0
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li x31,0
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.option push
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.option norelax
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la gp, __global_pointer$
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.option pop
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#if !defined(SKIP_MULTICORE)
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// Check hart id
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csrr a2, mhartid
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lui t0, %hi(_max_hart_id)
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add t0, t0, %lo(_max_hart_id)
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bgtu a2, t0, abort
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#endif // SKIP_MULTICORE
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// Allocate stacks
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la sp, _stack_start
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#if !defined(SKIP_MULTICORE)
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lui t0, %hi(_hart_stack_size)
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add t0, t0, %lo(_hart_stack_size)
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mul t0, a2, t0
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sub sp, sp, t0
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#endif // SKIP_MULTICORE
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// Set frame pointer
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add s0, sp, zero
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// Set trap handler
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la t0, _start_trap
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csrw mtvec, t0
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jal zero, _start_rust
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.cfi_endproc
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/*
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Trap entry point (_start_trap)
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Saves caller saved registers ra, t0..6, a0..7, calls _start_trap_rust,
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restores caller saved registers and then returns.
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*/
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.section .trap, "ax"
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.global _start_trap
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_start_trap:
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addi sp, sp, -16*REGBYTES
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STORE ra, 0*REGBYTES(sp)
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STORE t0, 1*REGBYTES(sp)
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STORE t1, 2*REGBYTES(sp)
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STORE t2, 3*REGBYTES(sp)
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STORE t3, 4*REGBYTES(sp)
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STORE t4, 5*REGBYTES(sp)
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STORE t5, 6*REGBYTES(sp)
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STORE t6, 7*REGBYTES(sp)
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STORE a0, 8*REGBYTES(sp)
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STORE a1, 9*REGBYTES(sp)
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STORE a2, 10*REGBYTES(sp)
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STORE a3, 11*REGBYTES(sp)
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STORE a4, 12*REGBYTES(sp)
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STORE a5, 13*REGBYTES(sp)
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STORE a6, 14*REGBYTES(sp)
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STORE a7, 15*REGBYTES(sp)
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jal ra, _start_trap_rust
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LOAD ra, 0*REGBYTES(sp)
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LOAD t0, 1*REGBYTES(sp)
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LOAD t1, 2*REGBYTES(sp)
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LOAD t2, 3*REGBYTES(sp)
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LOAD t3, 4*REGBYTES(sp)
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LOAD t4, 5*REGBYTES(sp)
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LOAD t5, 6*REGBYTES(sp)
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LOAD t6, 7*REGBYTES(sp)
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LOAD a0, 8*REGBYTES(sp)
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LOAD a1, 9*REGBYTES(sp)
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LOAD a2, 10*REGBYTES(sp)
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LOAD a3, 11*REGBYTES(sp)
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LOAD a4, 12*REGBYTES(sp)
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LOAD a5, 13*REGBYTES(sp)
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LOAD a6, 14*REGBYTES(sp)
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LOAD a7, 15*REGBYTES(sp)
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addi sp, sp, 16*REGBYTES
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mret
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/* Make sure there is an abort when linking */
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.section .text.init
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.globl abort
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abort:
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j abort
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