Re: RFA: PowerPC sim & GDB: use fixed register numbering

Andrew Cagney
2004-08-03T14:23:56Z

Have a look at the other sim-*.h files, you'll notice that most define
an enum namespace and not a series of magic constants. Can we expand
the table so that the constants aren't needed?

> + enum sim_ppc_regnum
> + {
> + /* General-purpose registers, r0 -- r31. */
> + sim_ppc_r0_regnum = 0,
> + sim_ppc_num_gprs = 32,
> +
> + /* Floating-point registers, f0 -- f31. */
> + sim_ppc_f0_regnum = 32,
> + sim_ppc_num_fprs = 32,
> +
> + /* Altivec vector registers, vr0 -- vr31. */
> + sim_ppc_vr0_regnum = 64,
> + sim_ppc_num_vrs = 32,
> +
> + /* SPE APU GPR upper halves. These are the upper 32 bits of the
> + gprs; there is one upper-half register for each gpr, so it is
> + appropriate to use sim_ppc_num_gprs for iterating through
> + these. */
> + sim_ppc_rh0_regnum = 96,
> +
> + /* SPE APU GPR full registers. Each of these registers is the
> + 64-bit concatenation of a 32-bit GPR (providing the lower bits)
> + and a 32-bit upper-half register (providing the higher bits).
> + As for the upper-half registers, it is appropriate to use
> + sim_ppc_num_gprs with these. */
> + sim_ppc_ev0_regnum = 128,
> +
> + /* Segment registers, sr0 -- sr15. */
> + sim_ppc_sr0_regnum = 160,
> + sim_ppc_num_srs = 16,
> +
> + /* Miscellaneous --- but non-SPR --- registers. */
> + sim_ppc_pc_regnum = 176,
> + sim_ppc_ps_regnum = 177,
> + sim_ppc_cr_regnum = 178,
> + sim_ppc_fpscr_regnum = 179,
> + sim_ppc_acc_regnum = 180,
> + sim_ppc_vscr_regnum = 181,
> +
> + /* Special-purpose registers. Each SPR is given a number equal to
> + its number in the ISA --- the number that appears in the mtspr
> + / mfspr instructions --- plus 1024. */
> + sim_ppc_spr0_regnum = 1024,
> + sim_ppc_num_sprs = 1024,
> + };

Looking at:

> + /* A table mapping register numbers (as received from GDB) to register
> + names. This table does not handle special-purpose registers: the
> + SPR whose number is N is assigned the register number 1024 + N. */
> + static const char *gdb_register_name_table[] = {
> +
> + /* General-purpose registers: 0 .. 31. */
> + "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
> + "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
> + "r16", "r17", "r18", "r19", "r20", "r21", "r22", "r23",
> + "r24", "r25", "r26", "r27", "r28", "r29", "r30", "r31",
> +
> + /* Floating-point registers: 32 .. 63. */
> + "f0", "f1", "f2", "f3", "f4", "f5", "f6", "f7",
> + "f8", "f9", "f10", "f11", "f12", "f13", "f14", "f15",
> + "f16", "f17", "f18", "f19", "f20", "f21", "f22", "f23",
> + "f24", "f25", "f26", "f27", "f28", "f29", "f30", "f31",
> +
> + /* Altivec registers: 64 .. 95. */
> + "vr0", "vr1", "vr2", "vr3", "vr4", "vr5", "vr6", "vr7",
> + "vr8", "vr9", "vr10", "vr11", "vr12", "vr13", "vr14", "vr15",
> + "vr16", "vr17", "vr18", "vr19", "vr20", "vr21", "vr22", "vr23",
> + "vr24", "vr25", "vr26", "vr27", "vr28", "vr29", "vr30", "vr31",
> +
> + /* SPE APU GPR upper halves: 96 .. 127. */
> + "rh0", "rh1", "rh2", "rh3", "rh4", "rh5", "rh6", "rh7",
> + "rh8", "rh9", "rh10", "rh11", "rh12", "rh13", "rh14", "rh15",
> + "rh16", "rh17", "rh18", "rh19", "rh20", "rh21", "rh22", "rh23",
> + "rh24", "rh25", "rh26", "rh27", "rh28", "rh29", "rh30", "rh31",
> +
> + /* SPE APU full 64-bit vector registers: 128 .. 159. */
> + "ev0", "ev1", "ev2", "ev3", "ev4", "ev5", "ev6", "ev7",
> + "ev8", "ev9", "ev10", "ev11", "ev12", "ev13", "ev14", "ev15",
> + "ev16", "ev17", "ev18", "ev19", "ev20", "ev21", "ev22", "ev23",
> + "ev24", "ev25", "ev26", "ev27", "ev28", "ev29", "ev30", "ev31",
> +
> + /* Segment registers: 160 .. 175. */
> + "sr0", "sr1", "sr2", "sr3", "sr4", "sr5", "sr6", "sr7",
> + "sr8", "sr9", "sr10", "sr11", "sr12", "sr13", "sr14", "sr15",
> +
> + /* Miscellaneous (not special-purpose!) registers: 176 .. 181. */
> + "pc", "ps", "cr", "fpscr", "acc", "vscr"
> + };

The old code, which did an under-the-covers call into gdb to map number
-> name, was bad and definitly needed to be replaced. The above though
could still do with some work - too much on the magic of those numbers
in gdb/sim-ppc.h :-(

Anyway, lets first get the enum in place.

Andrew