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spr: Add translation from SPR to special GPR number

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We will want to store some SPRs in the register file using
a set of "extra" registers. This provides a function for
doing the translation along with some SPR definitions.

This isn't used yet

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
This commit is contained in:
Benjamin Herrenschmidt
2019-10-31 12:09:14 +11:00
committed by Paul Mackerras
parent 5a0458dec1
commit afdd593502
1 changed files with 60 additions and 4 deletions
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64
common.vhdl
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@@ -12,10 +12,31 @@ package common is
function decode_spr_num(insn: std_ulogic_vector(31 downto 0)) return spr_num_t;
constant SPR_XER : spr_num_t := 1;
constant SPR_LR : spr_num_t := 8;
constant SPR_CTR : spr_num_t := 9;
constant SPR_TB : spr_num_t := 268;
constant SPR_XER : spr_num_t := 1;
constant SPR_LR : spr_num_t := 8;
constant SPR_CTR : spr_num_t := 9;
constant SPR_TB : spr_num_t := 268;
constant SPR_SRR0 : spr_num_t := 26;
constant SPR_SRR1 : spr_num_t := 27;
constant SPR_HSRR0 : spr_num_t := 314;
constant SPR_HSRR1 : spr_num_t := 315;
constant SPR_SPRG0 : spr_num_t := 272;
constant SPR_SPRG1 : spr_num_t := 273;
constant SPR_SPRG2 : spr_num_t := 274;
constant SPR_SPRG3 : spr_num_t := 275;
constant SPR_SPRG3U : spr_num_t := 259;
constant SPR_HSPRG0 : spr_num_t := 304;
constant SPR_HSPRG1 : spr_num_t := 305;
-- Some SPRs are stored in the register file, they use the magic
-- GPR numbers above 31.
--
-- The function fast_spr_num() returns the corresponding fast
-- pseudo-GPR number for a given SPR number. The result MSB
-- indicates if this is indeed a fast SPR. If clear, then
-- the SPR is not stored in the GPR file.
--
function fast_spr_num(spr: spr_num_t) return std_ulogic_vector;
-- The XER is split: the common bits (CA, OV, SO, OV32 and CA32) are
-- in the CR file as a kind of CR extension (with a separate write
@@ -282,4 +303,39 @@ package body common is
begin
return to_integer(unsigned(insn(15 downto 11) & insn(20 downto 16)));
end;
function fast_spr_num(spr: spr_num_t) return std_ulogic_vector is
variable n : integer range 0 to 31;
begin
case spr is
when SPR_LR =>
n := 0;
when SPR_CTR =>
n:= 1;
when SPR_SRR0 =>
n := 2;
when SPR_SRR1 =>
n := 3;
when SPR_HSRR0 =>
n := 4;
when SPR_HSRR1 =>
n := 5;
when SPR_SPRG0 =>
n := 6;
when SPR_SPRG1 =>
n := 7;
when SPR_SPRG2 =>
n := 8;
when SPR_SPRG3 | SPR_SPRG3U =>
n := 9;
when SPR_HSPRG0 =>
n := 10;
when SPR_HSPRG1 =>
n := 11;
when SPR_XER =>
n := 12;
when others =>
return "000000";
end case;
return "1" & std_ulogic_vector(to_unsigned(n, 5));
end;
end common;