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// TITLE("Unaligned Branch Tests")
//++
//
// Copyright (c) 1991 Microsoft Corporation
//
// Module Name:
//
// alignx.s
//
// Abstract:
//
// This module implements the unaligned branch tests.
//
// Author:
//
// David N. Cutler (davec) 27-Feb-1991
//
// Environment:
//
// User mode only.
//
// Revision History:
//
//--
#include "ksmips.h"
SBTTL("Unaligned BEQ/BNE/BC1F/BC1T Branch Tests")
//++
//
// Routine Description:
//
// The following routines implement beq/bne/bc1f/bc1t tests with an unaligned
// load word instruction in the delay slot.
//
// Arguments:
//
// a0 - Supplies first operand for branch test.
// a1 - Supplies second operate for branch test.
// a2 - Supplies a pointer to an unaligned word.
// a3 - Supplies a pointer to an aligned word that receives the result
// of the unaligned load.
//
// Return Value:
//
// A value of true is returned in the brancd was taken. Otherwise,
// FALSE is returned.
//
//--
LEAF_ENTRY(Beq)
.set noreorder
li v0,1 // set branched true
beq a0,a1,10f // if eq, branch
lw v1,0(a2) // load unaligned data
move v0,zero // set branched false
10: j ra // return
sw v1,0(a3) // store unaligned value
.set reorder
.end Beq
LEAF_ENTRY(Bne)
.set noreorder
li v0,1 // set branched true
bne a0,a1,10f // if eq, branch
lw v1,0(a2) // load unaligned data
move v0,zero // set branched false
10: j ra // return
sw v1,0(a3) // store unaligned value
.set reorder
.end Bne
LEAF_ENTRY(Bc1f)
.set noreorder
mtc1 a0,f0 // set comparand 1
mtc1 a1,f2 // set comparand 2
li v0,1 // set branched true
c.eq.s f0,f2 // compare for equality
bc1f 10f // if f, branch
lw v1,0(a2) // load unaligned data
move v0,zero // set branched false
10: j ra // return
sw v1,0(a3) // store unaligned value
.set reorder
.end Bc1f
LEAF_ENTRY(Bc1t)
.set noreorder
mtc1 a0,f0 // set comparand 1
mtc1 a1,f2 // set comparand 2
li v0,1 // set branched true
c.eq.s f0,f2 // compare for equality
bc1t 10f // if t, branch
lw v1,0(a2) // load unaligned data
move v0,zero // set branched false
10: j ra // return
sw v1,0(a3) // store unaligned value
.set reorder
.end Bc1t
SBTTL("Unaligned BLEZ/BLTZ/BGEZ/BGTZ/BGEZAL/BLTZAL Branch Tests")
//++
//
// Routine Description:
//
// The following routines implement blez/bltz/bgez/bgtz/bgezal/bltzal
// tests with an unaligned load word instruction in the delay slot.
//
// Arguments:
//
// a0 - Supplies the operand for branch test.
// a1 - Supplies a pointer to an unaligned word.
// a2 - Supplies a pointer to an aligned word that receives the result
// of the unaligned load.
//
// Return Value:
//
// A value of true is returned in the branch was taken. Otherwise,
// FALSE is returned.
//
//--
LEAF_ENTRY(Blez)
.set noreorder
li v0,1 // set branched true
blez a0,10f // if lez, branch
lw v1,0(a1) // load unaligned data
move v0,zero // set branched false
10: j ra // return
sw v1,0(a2) // store unaligned value
.set reorder
.end Blez
LEAF_ENTRY(Bltz)
.set noreorder
li v0,1 // set branched true
bltz a0,10f // if ltz, branch
lw v1,0(a1) // load unaligned data
move v0,zero // set branched false
10: j ra // return
sw v1,0(a2) // store unaligned value
.set reorder
.end Bltz
LEAF_ENTRY(Bgez)
.set noreorder
li v0,1 // set branched true
bgez a0,10f // if gez, branch
lw v1,0(a1) // load unaligned data
move v0,zero // set branched false
10: j ra // return
sw v1,0(a2) // store unaligned value
.set reorder
.end Bgez
LEAF_ENTRY(Bgtz)
.set noreorder
li v0,1 // set branched true
bgtz a0,10f // if gtz, branch
lw v1,0(a1) // load unaligned data
move v0,zero // set branched false
10: j ra // return
sw v1,0(a2) // store unaligned value
.set reorder
.end Bgtz
LEAF_ENTRY(Bgezal)
.set noreorder
sw ra,4 * 4(sp) // save return address
move v0,zero // set branched false
bgezal a0,10f // if gez, branch and link
lw v1,0(a1) // load unaligned data
lw ra,4 * 4(sp) // restore return address
sw v1,0(a2) // store unaligned value
j ra // return
nop //
10: j ra // return
li v0,1 // set branched true
.set reorder
.end Bgezal
LEAF_ENTRY(Bltzal)
.set noreorder
sw ra,4 * 4(sp) // save return address
move v0,zero // set branched false
bltzal a0,10f // if ltz, branch and link
lw v1,0(a1) // load unaligned data
lw ra,4 * 4(sp) // restore return address
sw v1,0(a2) // store unaligned value
j ra // return
nop //
10: j ra // return
li v0,1 // set branched true
.set reorder
.end Bltzal
SBTTL("Unaligned JAL/J Tests")
//++
//
// Routine Description:
//
// The following routines implement jal/j tests with an unaligned
// load word instruction in the delay slot.
//
// Arguments:
//
// a0 - Supplies a pointer to an unaligned word.
// a1 - Supplies a pointer to an aligned word that receives the result
// of the unaligned load.
//
// Return Value:
//
// A value of true is returned in the brancd was taken. Otherwise,
// FALSE is returned.
//
//--
LEAF_ENTRY(Jal)
.set noreorder
sw ra,4 * 4(sp) // save return address
move v0,zero // set branched false
jal 10f // jump and link
lw v1,0(a0) // load unaligned data
lw ra,4 * 4(sp) // restore return address
sw v1,0(a1) // store unaligned value
j ra // return
nop //
10: j ra // return
li v0,1 // set branched true
.set reorder
.end Jal
LEAF_ENTRY(Jalr)
.set noreorder
sw ra,4 * 4(sp) // save return address
move v0,zero // set branched false
la t0,10f // get destination address
jal t0 // jump
lw v1,0(a0) // load unaligned data
lw ra,4 * 4(sp) // restore return address
sw v1,0(a1) // store unaligned value
j ra // return
nop //
10: j ra // jump back
li v0,1 // set branched true
.set reorder
.end Jalr
LEAF_ENTRY(J)
.set noreorder
sw ra,4 * 4(sp) // save return address
move v0,zero // set branched false
j 10f // jump
lw v1,0(a0) // load unaligned data
20: lw ra,4 * 4(sp) // restore return address
sw v1,0(a1) // store unaligned value
j ra // return
nop //
10: j 20b // jump back
li v0,1 // set branched true
.set reorder
.end J
LEAF_ENTRY(Jr)
.set noreorder
sw ra,4 * 4(sp) // save return address
move v0,zero // set branched false
la t0,10f // get destination address
j t0 // jump
lw v1,0(a0) // load unaligned data
20: lw ra,4 * 4(sp) // restore return address
sw v1,0(a1) // store unaligned value
j ra // return
nop //
10: j 20b // return
li v0,1 // set branched true
.set reorder
.end Jr
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