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cmd/internal/asm/ppc64: support 34b ADD/MOVD $const, Rx
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For constant signed values which require 34b to represent,
the assembler will generate a pli instruction on
linux/power10/PPC64 instead of loading a constant.

Similarly, ADD is extended to support 34b signed constants.
On linux/power10/PPC64, this generates a paddi instruction.
For assembler consistency, a second form is added if paddi
cannot be used. The second form is provided for assembly
writers.

Change-Id: I98144306af766b02fbbe36b72856a23cdf51d247
Reviewed-on: https://go-review.googlesource.com/c/go/+/528317
TryBot-Result: Gopher Robot <gobot@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Eli Bendersky <eliben@google.com>
Run-TryBot: Paul Murphy <murp@ibm.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
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@pmur
pmur committed Oct 3, 2023
1 parent 6bcf176 commit e9379a8
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Showing 3 changed files with 29 additions and 15 deletions.
4 changes: 4 additions & 0 deletions src/cmd/asm/internal/asm/testdata/ppc64.s
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Expand Up @@ -33,6 +33,10 @@ TEXT asmtest(SB),DUPOK|NOSPLIT,$0
MOVD $2147483649, R5 // 6405800060a50001 or 0600800038a00001
// Hex constant 0xFFFFFFFF80000001
MOVD $-2147483647, R5 // 3ca0800060a50001 or 0603800038a00001
// Hex constant 0xFFFFFFFE00000000 (load of constant on < power10, pli on >= power10
MOVD $-8589934592, R5 // 3ca00000e8a50000 or 0602000038a00000
// Hex constant 0xFFFFFFFE00000000
ADD $-8589934592, R5 // 3fe0fffe63ff00007bff83e463ff00007cbf2a14 or 0602000038a50000
MOVD 8(R3), R4 // e8830008
MOVD (R3)(R4), R5 // 7ca4182a
MOVD (R3)(R0), R5 // 7ca0182a
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32 changes: 19 additions & 13 deletions src/cmd/internal/obj/ppc64/asm9.go
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Expand Up @@ -545,7 +545,7 @@ type PrefixableOptab struct {
//
// This requires an ISA 3.1 compatible cpu (e.g Power10), and when linking externally an ELFv2 1.5 compliant.
var prefixableOptab = []PrefixableOptab{
{Optab: Optab{as: AMOVD, a1: C_LCON, a6: C_REG, type_: 19, size: 8}, minGOPPC64: 10, pfxsize: 8},
{Optab: Optab{as: AMOVD, a1: C_S34CON, a6: C_REG, type_: 19, size: 8}, minGOPPC64: 10, pfxsize: 8},
{Optab: Optab{as: AMOVD, a1: C_ADDR, a6: C_REG, type_: 75, size: 8}, minGOPPC64: 10, pfxsize: 8},
{Optab: Optab{as: AMOVD, a1: C_TLS_LE, a6: C_REG, type_: 79, size: 8}, minGOPPC64: 10, pfxsize: 8},
{Optab: Optab{as: AMOVD, a1: C_TLS_IE, a6: C_REG, type_: 80, size: 12}, minGOPPC64: 10, pfxsize: 12},
Expand Down Expand Up @@ -578,6 +578,8 @@ var prefixableOptab = []PrefixableOptab{

{Optab: Optab{as: AADD, a1: C_LCON, a2: C_REG, a6: C_REG, type_: 22, size: 12}, minGOPPC64: 10, pfxsize: 8},
{Optab: Optab{as: AADD, a1: C_LCON, a6: C_REG, type_: 22, size: 12}, minGOPPC64: 10, pfxsize: 8},
{Optab: Optab{as: AADD, a1: C_S34CON, a2: C_REG, a6: C_REG, type_: 22, size: 20}, minGOPPC64: 10, pfxsize: 8},
{Optab: Optab{as: AADD, a1: C_S34CON, a6: C_REG, type_: 22, size: 20}, minGOPPC64: 10, pfxsize: 8},
}

var oprange [ALAST & obj.AMask][]Optab
Expand Down Expand Up @@ -2978,7 +2980,7 @@ func asmout(c *ctxt9, p *obj.Prog, o *Optab, out *[5]uint32) {
o1 = AOP_IRR(c.opirr(AADDIS), uint32(p.To.Reg), uint32(r), uint32(v)>>16)
}

case 22: /* add $lcon/$andcon,r1,r2 ==> oris+ori+add/ori+add */
case 22: /* add $lcon/$andcon,r1,r2 ==> oris+ori+add/ori+add, add $s34con,r1 ==> addis+ori+slw+ori+add */
if p.To.Reg == REGTMP || p.Reg == REGTMP {
c.ctxt.Diag("can't synthesize large constant\n%v", p)
}
Expand All @@ -2990,19 +2992,23 @@ func asmout(c *ctxt9, p *obj.Prog, o *Optab, out *[5]uint32) {
if p.From.Sym != nil {
c.ctxt.Diag("%v is not supported", p)
}
// If operand is ANDCON, generate 2 instructions using
// ORI for unsigned value; with LCON 3 instructions.
if o.size == 8 {
o1 = LOP_IRR(OP_ORI, REGTMP, REGZERO, uint32(int32(d)))
o2 = AOP_RRR(c.oprrr(p.As), uint32(p.To.Reg), REGTMP, uint32(r))
} else {
o1 = loadu32(REGTMP, d)
o2 = LOP_IRR(OP_ORI, REGTMP, REGTMP, uint32(int32(d)))
o3 = AOP_RRR(c.oprrr(p.As), uint32(p.To.Reg), REGTMP, uint32(r))
}

if o.ispfx {
o1, o2 = pfxadd(int16(p.To.Reg), int16(r), PFX_R_ABS, d)
} else if o.size == 8 {
o1 = LOP_IRR(OP_ORI, REGTMP, REGZERO, uint32(int32(d))) // tmp = uint16(d)
o2 = AOP_RRR(c.oprrr(p.As), uint32(p.To.Reg), REGTMP, uint32(r)) // to = tmp + from
} else if o.size == 12 {
// Note, o1 is ADDIS if d is negative, ORIS otherwise.
o1 = loadu32(REGTMP, d) // tmp = d & 0xFFFF0000
o2 = LOP_IRR(OP_ORI, REGTMP, REGTMP, uint32(int32(d))) // tmp |= d & 0xFFFF
o3 = AOP_RRR(c.oprrr(p.As), uint32(p.To.Reg), REGTMP, uint32(r)) // to = from + tmp
} else {
// For backwards compatibility with GOPPC64 < 10, generate 34b constants in register.
o1 = LOP_IRR(OP_ADDIS, REGZERO, REGTMP, uint32(d>>32)) // tmp = sign_extend((d>>32)&0xFFFF0000)
o2 = LOP_IRR(OP_ORI, REGTMP, REGTMP, uint32(d>>16)) // tmp |= (d>>16)&0xFFFF
o3 = AOP_RLDIC(OP_RLDICR, REGTMP, REGTMP, 16, 63-16) // tmp <<= 16
o4 = LOP_IRR(OP_ORI, REGTMP, REGTMP, uint32(uint16(d))) // tmp |= d&0xFFFF
o5 = AOP_RRR(c.oprrr(p.As), uint32(p.To.Reg), REGTMP, uint32(r))
}

case 23: /* and $lcon/$addcon,r1,r2 ==> oris+ori+and/addi+and */
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8 changes: 6 additions & 2 deletions src/cmd/internal/obj/ppc64/obj9.go
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Original file line number Diff line number Diff line change
Expand Up @@ -81,10 +81,14 @@ func progedit(ctxt *obj.Link, p *obj.Prog, newprog obj.ProgAlloc) {

case AMOVD:
// 32b constants (signed and unsigned) can be generated via 1 or 2 instructions.
// All others must be placed in memory and loaded.
isS32 := int64(int32(p.From.Offset)) == p.From.Offset
isU32 := uint64(uint32(p.From.Offset)) == uint64(p.From.Offset)
if p.From.Type == obj.TYPE_CONST && p.From.Name == obj.NAME_NONE && p.From.Reg == 0 && !isS32 && !isU32 {

// If prefixed instructions are supported, a 34b signed constant can be generated by one pli instruction.
isS34 := pfxEnabled && (p.From.Offset<<30)>>30 == p.From.Offset

// If the constant cannot be generated with 2 or less instructions, it must be placed in memory and loaded.
if p.From.Type == obj.TYPE_CONST && p.From.Name == obj.NAME_NONE && p.From.Reg == 0 && !isS32 && !isU32 && !isS34 {
p.From.Type = obj.TYPE_MEM
p.From.Sym = ctxt.Int64Sym(p.From.Offset)
p.From.Name = obj.NAME_EXTERN
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