Add fgt.[hsd] and fge.[hsd] pseudo-instructions

Those two pseudo-instructions are trivial and also already implmented in the
binutils[1] and LLVM[2].

[1] bminor/binutils-gdb@e23eba9
[2] llvm/llvm-project@8408079

NOTE: bintuils supports those 2 kind of pseudo-instructions since RISC-V support began.

Author: kito-cheng

src/asm-manual.adoc

@@ -1067,12 +1067,18 @@ srli rd, rd, XLEN - 32
 |fmv.h frd, frs               | fsgnj.h frd, frs, frs                                         | Copy half-precision register |
 |fabs.h frd, frs              | fsgnjx.h frd, frs, frs                                        | Half-precision absolute value |
 |fneg.h frd, frs              | fsgnjn.h frd, frs, frs                                        | Half-precision negate |
+|fgt.h rd, frs, frt           | flt.h rd, frt, frs                                            | Half-precision > |
+|fge.h rd, frs, frt           | fle.h rd, frt, frs                                            | Half-precision >= |
 |fmv.s frd, frs               | fsgnj.s frd, frs, frs                                         | Copy single-precision register |
 |fabs.s frd, frs              | fsgnjx.s frd, frs, frs                                        | Single-precision absolute value |
 |fneg.s frd, frs              | fsgnjn.s frd, frs, frs                                        | Single-precision negate |
+|fgt.s rd, frs, frt           | flt.s rd, frt, frs                                            | Single-precision > |
+|fge.s rd, frs, frt           | fle.s rd, frt, frs                                            | Single-precision >= |
 |fmv.d frd, frs               | fsgnj.d frd, frs, frs                                         | Copy double-precision register |
 |fabs.d frd, frs              | fsgnjx.d frd, frs, frs                                        | Double-precision absolute value |
 |fneg.d frd, frs              | fsgnjn.d frd, frs, frs                                        | Double-precision negate |
+|fgt.d rd, frs, frt           | flt.d rd, frt, frs                                            | Double-precision > |
+|fge.d rd, frs, frt           | fle.d rd, frt, frs                                            | Double-precision >= |
 |beqz rs, offset              | beq rs, x0, offset                                            | Branch if = zero |
 |bnez rs, offset              | bne rs, x0, offset                                            | Branch if != zero |
 |blez rs, offset              | bge x0, rs, offset                                            | Branch if ≤ zero |