Merge pull request #240 from riscv-non-isa/simplify-lo12-calculation

riscv-elf: Use simpler equivalent expression for LO12 relocations

Author: kito-cheng

riscv-elf.adoc

@@ -468,8 +468,8 @@ is followed by an I-Type instruction (add immediate or load) with an
 calculated like this:
 
 [horizontal]
-HI20:: `((symbol_address + 0x800) >> 12)`
-LO12:: `symbol_address - (hi20 << 12)`
+HI20:: `(symbol_address + 0x800) >> 12`
+LO12:: `symbol_address`
 
 The following assembly and relocations show loading an absolute address:
 
@@ -610,8 +610,8 @@ immediate on the add, load or store instruction the linker finds the
 instruction. The addresses for pair of relocations are calculated like this:
 
 [horizontal]
-HI20:: `((symbol_address - hi20_reloc_offset + 0x800) >> 12)`
-LO12:: `symbol_address - hi20_reloc_offset - (hi20 << 12)`
+HI20:: `(symbol_address - hi20_reloc_offset + 0x800) >> 12`
+LO12:: `symbol_address - hi20_reloc_offset`
 
 The successive instruction has a signed 12-bit immediate so the value of the
 preceding high 20-bit relocation may have 1 added to it.