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156 lines
2.4 KiB
156 lines
2.4 KiB
.section .init
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.global _start
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.type _start,@function
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_start:
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#ifndef VEXRISCV_RWMTVEC
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j _crtInit
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nop
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nop
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nop
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nop
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nop
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nop
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nop
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j trap_entry
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_crtInit:
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#endif
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.cfi_startproc
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.cfi_undefined ra
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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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la sp, _sp
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#ifndef VEXRISCV_VOLATILE
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/* Load data section */
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la a0, _data_lma
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la a1, _data
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la a2, _edata
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bgeu a1, a2, 2f
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1:
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lw t0, (a0)
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sw t0, (a1)
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addi a0, a0, 4
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addi a1, a1, 4
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bltu a1, a2, 1b
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2:
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#endif
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/* Clear bss section */
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la a0, __bss_start
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la a1, _end
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bgeu a0, a1, 2f
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1:
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sw zero, (a0)
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addi a0, a0, 4
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bltu a0, a1, 1b
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2:
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/* Call global constructors */
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la a0, __libc_fini_array
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call atexit
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call __libc_init_array
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auipc ra, 0
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addi sp, sp, -16
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sw ra, 8(sp)
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/* Enable Interrupts and set trap vector */
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#ifndef VEXRISCV_RWMTVEC
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la a0, trap_entry
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csrw mtvec, a0
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#endif
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li a0, 0x880 //880 enable timer + external interrupts
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csrw mie, a0
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li a0, 0x1808 //1808 enable interrupts
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csrw mstatus, a0
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/* argc = argv = 0 */
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li a0, 0
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li a1, 0
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call main
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tail exit
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1:
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j 1b
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.cfi_endproc
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.align 4
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.weak trap_entry
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.global trap_entry
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trap_entry:
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addi sp, sp, -32*4
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sw x1, 1*4(sp)
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sw x2, 2*4(sp)
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sw x3, 3*4(sp)
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sw x4, 4*4(sp)
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sw x5, 5*4(sp)
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sw x6, 6*4(sp)
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sw x7, 7*4(sp)
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sw x8, 8*4(sp)
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sw x9, 9*4(sp)
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sw x10, 10*4(sp)
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sw x11, 11*4(sp)
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sw x12, 12*4(sp)
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sw x13, 13*4(sp)
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sw x14, 14*4(sp)
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sw x15, 15*4(sp)
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sw x16, 16*4(sp)
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sw x17, 17*4(sp)
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sw x18, 18*4(sp)
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sw x19, 19*4(sp)
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sw x20, 20*4(sp)
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sw x21, 21*4(sp)
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sw x22, 22*4(sp)
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sw x23, 23*4(sp)
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sw x24, 24*4(sp)
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sw x25, 25*4(sp)
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sw x26, 26*4(sp)
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sw x27, 27*4(sp)
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sw x28, 28*4(sp)
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sw x29, 29*4(sp)
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sw x30, 30*4(sp)
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sw x31, 31*4(sp)
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call irqCallback
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lw x1, 1*4(sp)
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lw x2, 2*4(sp)
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lw x3, 3*4(sp)
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lw x4, 4*4(sp)
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lw x5, 5*4(sp)
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lw x6, 6*4(sp)
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lw x7, 7*4(sp)
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lw x8, 8*4(sp)
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lw x9, 9*4(sp)
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lw x10, 10*4(sp)
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lw x11, 11*4(sp)
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lw x12, 12*4(sp)
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lw x13, 13*4(sp)
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lw x14, 14*4(sp)
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lw x15, 15*4(sp)
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lw x16, 16*4(sp)
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lw x17, 17*4(sp)
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lw x18, 18*4(sp)
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lw x19, 19*4(sp)
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lw x20, 20*4(sp)
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lw x21, 21*4(sp)
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lw x22, 22*4(sp)
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lw x23, 23*4(sp)
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lw x24, 24*4(sp)
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lw x25, 25*4(sp)
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lw x26, 26*4(sp)
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lw x27, 27*4(sp)
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lw x28, 28*4(sp)
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lw x29, 29*4(sp)
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lw x30, 30*4(sp)
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lw x31, 31*4(sp)
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addi sp, sp, 32*4
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mret
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.weak irqCallback
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irqCallback:
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1:
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j 1b
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