512 lines
8.4 KiB
ArmAsm
512 lines
8.4 KiB
ArmAsm
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/*
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* Minimal Alpha system boot code.
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*
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* Copyright Linaro Ltd 2019
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*/
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.set noat
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.set nomacro
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.arch ev6
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.text
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.macro load_pci_io reg
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/* For typhoon, this is
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* 0xfffffc0000000000 -- kseg identity map
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* + 0x10000000000 -- typhoon pio base
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* + 0x1fc000000 -- typhoon pchip0 pci base
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* = 0xfffffd01fc000000
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*/
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ldah \reg, -3 /* ff..fd0000 */
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lda \reg, 0x1fc(\reg) /* ff..fd01fc */
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sll \reg, 24, \reg
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.endm
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#define com1Rbr 0x3f8
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#define com1Thr 0x3f8
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#define com1Ier 0x3f9
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#define com1Iir 0x3fa
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#define com1Lcr 0x3fb
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#define com1Mcr 0x3fc
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#define com1Lsr 0x3fd
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#define com1Msr 0x3fe
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#define com1Scr 0x3ff
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#define com1Dll 0x3f8
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#define com1Dlm 0x3f9
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#define PAL_halt 0
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#define PAL_wrent 52
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#define PAL_wrkgp 55
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.text
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.p2align 4
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.globl _start
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.ent _start
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_start:
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br $gp, .+4
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ldah $gp, 0($gp) !gpdisp!1
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lda $gp, 0($gp) !gpdisp!1
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ldah $sp, $stack_end($gp) !gprelhigh
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lda $sp, $stack_end($sp) !gprellow
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/* Install kernel gp for exception handlers. */
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mov $gp, $16
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call_pal PAL_wrkgp
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/* Install exception handlers. */
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ldah $16, entInt($gp) !gprelhigh
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lda $16, entInt($16) !gprellow
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lda $17, 0
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call_pal PAL_wrent
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ldah $16, entArith($gp) !gprelhigh
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lda $16, entArith($16) !gprellow
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lda $17, 1
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call_pal PAL_wrent
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ldah $16, entMM($gp) !gprelhigh
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lda $16, entMM($16) !gprellow
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lda $17, 2
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call_pal PAL_wrent
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ldah $16, entIF($gp) !gprelhigh
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lda $16, entIF($16) !gprellow
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lda $17, 3
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call_pal PAL_wrent
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ldah $16, entUna($gp) !gprelhigh
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lda $16, entUna($16) !gprellow
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lda $17, 4
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call_pal PAL_wrent
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ldah $16, entSys($gp) !gprelhigh
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lda $16, entSys($16) !gprellow
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lda $17, 5
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call_pal PAL_wrent
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/*
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* Initialize COM1.
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*/
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load_pci_io $1
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lda $2, 0x87 /* outb(0x87, com1Lcr); */
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stb $2, com1Lcr($1)
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stb $31, com1Dlm($1) /* outb(0, com1Dlm); */
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lda $2, 3 /* baudconst 3 => 56000 */
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stb $2, com1Dll($1) /* outb(baudconst, com1Dll); */
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lda $2, 0x07
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stb $2, com1Lcr($1) /* outb(0x07, com1Lcr) */
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lda $2, 0x0f
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stb $2, com1Mcr($1) /* outb(0x0f, com1Mcr) */
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bsr $26, main !samegp
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/* fall through to _exit */
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.end _start
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.globl _exit
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.ent _exit
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_exit:
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.frame $sp, 0, $26, 0
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.prologue 0
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/* We cannot return an error code. */
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call_pal PAL_halt
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.end _exit
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/*
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* We have received an exception that we don't handle. Log and exit.
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*/
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.ent log_exit
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log_exit:
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entInt:
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entArith:
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entMM:
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entIF:
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entUna:
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entSys:
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ldah $16, $errormsg($gp) !gprelhigh
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lda $16, $errormsg($16) !gprellow
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bsr $26, __sys_outs !samegp
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bsr $26, _exit !samegp
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.end log_exit
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.section .rodata
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$errormsg:
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.string "Terminated by exception.\n"
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.previous
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/*
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* Helper Functions
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*/
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/* Output a single character to serial port */
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.global __sys_outc
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.ent __sys_outc
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__sys_outc:
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.frame $sp, 0, $26, 0
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.prologue 0
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load_pci_io $1
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/*
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* while ((inb(com1Lsr) & 0x20) == 0)
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* continue;
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*/
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1: ldbu $0, com1Lsr($1)
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and $0, 0x20, $0
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beq $0, 1b
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/* outb(c, com1Thr); */
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stb $16, com1Thr($1)
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ret
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.end __sys_outc
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/* Output a nul-terminated string to serial port */
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.global __sys_outs
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.ent __sys_outs
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__sys_outs:
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.frame $sp, 0, $26, 0
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.prologue 0
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load_pci_io $1
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ldbu $2, 0($16)
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beq $2, 9f
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/*
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* while ((inb(com1Lsr) & 0x20) == 0)
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* continue;
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*/
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1: ldbu $0, com1Lsr($1)
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and $0, 0x20, $0
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beq $0, 1b
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/* outb(c, com1Thr); */
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stb $2, com1Thr($1)
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addq $16, 1, $16
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ldbu $2, 0($16)
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bne $2, 1b
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9: ret
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.end __sys_outs
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/*
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* Division routines that are normally in libc.
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*
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* These do not follow the C calling convention. Arguments are in $24+$25,
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* the result is in $27. Register $28 may be clobbered; everything else
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* must be saved.
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*
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* We store the remainder in $28, so that we can share code.
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*
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* We do not signal divide by zero.
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*/
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/*
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* Unsigned 64-bit division.
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*/
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.globl __divqu
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.ent __divqu
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__divqu:
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.frame $sp, 48, $23
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subq $sp, 48, $sp
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stq $0, 0($sp)
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stq $1, 8($sp)
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stq $2, 16($sp)
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stq $3, 24($sp)
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stq $4, 32($sp)
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.prologue 0
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#define mask $0
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#define divisor $1
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#define compare $2
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#define tmp1 $3
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#define tmp2 $4
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#define quotient $27
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#define modulus $28
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mov $24, modulus
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mov $25, divisor
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mov $31, quotient
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mov 1, mask
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beq $25, 9f
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/* Shift left until divisor >= modulus. */
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1: cmpult divisor, modulus, compare
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blt divisor, 2f
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addq divisor, divisor, divisor
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addq mask, mask, mask
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bne compare, 1b
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2: addq quotient, mask, tmp2
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srl mask, 1, mask
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cmpule divisor, modulus, compare
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subq modulus, divisor, tmp1
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cmovne compare, tmp2, quotient
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srl divisor, 1, divisor
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cmovne compare, tmp1, modulus
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bne mask, 2b
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9: ldq $0, 0($sp)
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ldq $1, 8($sp)
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ldq $2, 16($sp)
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ldq $3, 24($sp)
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ldq $4, 32($sp)
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addq $sp, 48, $sp
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ret $31, ($23), 1
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#undef mask
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#undef divisor
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#undef compare
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#undef tmp1
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#undef tmp2
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#undef quotient
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#undef modulus
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.end __divqu
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/*
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* Unsigned 64-bit remainder.
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* Note that __divqu above leaves the result in $28.
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*/
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.globl __remqu
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.ent __remqu
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__remqu:
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.frame $sp, 16, $23
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subq $sp, 16, $sp
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stq $23, 0($sp)
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.prologue 0
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bsr $23, __divqu
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ldq $23, 0($sp)
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mov $28, $27
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addq $sp, 16, $sp
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ret $31, ($23), 1
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.end __remqu
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/*
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* Signed 64-bit division.
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*/
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.globl __divqs
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.ent __divqs
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__divqs:
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.prologue 0
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/* Common case: both arguments are positive. */
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bis $24, $25, $28
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bge $28, __divqu
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/* At least one argument is negative. */
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subq $sp, 32, $sp
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stq $23, 0($sp)
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stq $24, 8($sp)
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stq $25, 16($sp)
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/* Compute absolute values. */
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subq $31, $24, $28
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cmovlt $24, $28, $24
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subq $31, $25, $28
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cmovlt $25, $28, $25
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bsr $23, __divqu
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ldq $24, 8($sp)
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ldq $25, 16($sp)
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/* -a / b = a / -b = -(a / b) */
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subq $31, $27, $23
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xor $24, $25, $28
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cmovlt $28, $23, $27
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ldq $23, 0($sp)
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addq $sp, 32, $sp
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ret $31, ($23), 1
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.end __divqs
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/*
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* Signed 64-bit remainder.
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*/
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.globl __remqs
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.ent __remqs
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__remqs:
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.prologue 0
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/* Common case: both arguments are positive. */
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bis $24, $25, $28
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bge $28, __remqu
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/* At least one argument is negative. */
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subq $sp, 32, $sp
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stq $23, 0($sp)
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stq $24, 8($sp)
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stq $25, 16($sp)
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/* Compute absolute values. */
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subq $31, $24, $28
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cmovlt $24, $28, $24
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subq $31, $25, $28
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cmovlt $25, $28, $25
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bsr $23, __divqu
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ldq $23, 0($sp)
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ldq $24, 8($sp)
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ldq $25, 16($sp)
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/* -a % b = -(a % b); a % -b = a % b. */
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subq $31, $28, $27
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cmovge $24, $28, $27
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addq $sp, 32, $sp
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ret $31, ($23), 1
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.end __remqs
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/*
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* Unsigned 32-bit division.
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*/
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.globl __divlu
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.ent __divlu
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__divlu:
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.frame $sp, 32, $23
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subq $sp, 32, $sp
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stq $23, 0($sp)
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stq $24, 8($sp)
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stq $25, 16($sp)
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.prologue 0
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/* Zero extend and use the 64-bit routine. */
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zap $24, 0xf0, $24
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zap $25, 0xf0, $25
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bsr $23, __divqu
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addl $27, 0, $27
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ldq $23, 0($sp)
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ldq $24, 8($sp)
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ldq $25, 16($sp)
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addq $sp, 32, $sp
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ret $31, ($23), 1
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.end __divlu
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/*
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* Unsigned 32-bit remainder.
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*/
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.globl __remlu
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.ent __remlu
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__remlu:
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.frame $sp, 32, $23
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subq $sp, 32, $sp
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||
|
|
stq $23, 0($sp)
|
||
|
|
stq $24, 8($sp)
|
||
|
|
stq $25, 16($sp)
|
||
|
|
.prologue 0
|
||
|
|
|
||
|
|
/* Zero extend and use the 64-bit routine. */
|
||
|
|
zap $24, 0xf0, $24
|
||
|
|
zap $25, 0xf0, $25
|
||
|
|
bsr $23, __divqu
|
||
|
|
|
||
|
|
/* Recall that the remainder is returned in $28. */
|
||
|
|
addl $28, 0, $27
|
||
|
|
ldq $23, 0($sp)
|
||
|
|
ldq $24, 8($sp)
|
||
|
|
ldq $25, 16($sp)
|
||
|
|
addq $sp, 32, $sp
|
||
|
|
ret $31, ($23), 1
|
||
|
|
.end __remlu
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Signed 32-bit division.
|
||
|
|
*/
|
||
|
|
|
||
|
|
.globl __divls
|
||
|
|
.ent __divls
|
||
|
|
__divls:
|
||
|
|
.frame $sp, 32, $23
|
||
|
|
subq $sp, 32, $sp
|
||
|
|
stq $23, 0($sp)
|
||
|
|
stq $24, 8($sp)
|
||
|
|
stq $25, 16($sp)
|
||
|
|
.prologue 0
|
||
|
|
|
||
|
|
/* Sign extend. */
|
||
|
|
addl $24, 0, $24
|
||
|
|
addl $25, 0, $25
|
||
|
|
|
||
|
|
/* Compute absolute values. */
|
||
|
|
subq $31, $24, $28
|
||
|
|
cmovlt $24, $28, $24
|
||
|
|
subq $31, $25, $28
|
||
|
|
cmovlt $25, $28, $25
|
||
|
|
|
||
|
|
bsr $23, __divqu
|
||
|
|
|
||
|
|
ldq $24, 8($sp)
|
||
|
|
ldq $25, 16($sp)
|
||
|
|
|
||
|
|
/* Negate the unsigned result, if necessary. */
|
||
|
|
xor $24, $25, $28
|
||
|
|
subl $31, $27, $23
|
||
|
|
addl $27, 0, $27
|
||
|
|
addl $28, 0, $28
|
||
|
|
cmovlt $28, $23, $27
|
||
|
|
|
||
|
|
ldq $23, 0($sp)
|
||
|
|
addq $sp, 32, $sp
|
||
|
|
ret $31, ($23), 1
|
||
|
|
.end __divls
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Signed 32-bit remainder.
|
||
|
|
*/
|
||
|
|
|
||
|
|
.globl __remls
|
||
|
|
.ent __remls
|
||
|
|
__remls:
|
||
|
|
.frame $sp, 32, $23
|
||
|
|
subq $sp, 32, $sp
|
||
|
|
stq $23, 0($sp)
|
||
|
|
stq $24, 8($sp)
|
||
|
|
stq $25, 16($sp)
|
||
|
|
.prologue 0
|
||
|
|
|
||
|
|
/* Sign extend. */
|
||
|
|
addl $24, 0, $24
|
||
|
|
addl $25, 0, $25
|
||
|
|
|
||
|
|
/* Compute absolute values. */
|
||
|
|
subq $31, $24, $28
|
||
|
|
cmovlt $24, $28, $24
|
||
|
|
subq $31, $25, $28
|
||
|
|
cmovlt $25, $28, $25
|
||
|
|
|
||
|
|
bsr $23, __divqu
|
||
|
|
|
||
|
|
ldq $23, 0($sp)
|
||
|
|
ldq $24, 8($sp)
|
||
|
|
ldq $25, 16($sp)
|
||
|
|
|
||
|
|
/* Negate the unsigned result, if necessary. */
|
||
|
|
subl $31, $28, $27
|
||
|
|
addl $28, 0, $28
|
||
|
|
cmovge $24, $28, $27
|
||
|
|
|
||
|
|
addq $sp, 32, $sp
|
||
|
|
ret $31, ($23), 1
|
||
|
|
.end __remls
|
||
|
|
|
||
|
|
.data
|
||
|
|
.p2align 4
|
||
|
|
stack:
|
||
|
|
.skip 65536
|
||
|
|
$stack_end:
|
||
|
|
.type stack,@object
|
||
|
|
.size stack, . - stack
|