RISC-V呼叫约定的ABI注册名称 [英] ABI Register Names for RISC-V Calling Convention

问题描述

我对RISC-V ABI寄存器名称感到困惑.例如，第85页的"RISC-V指令集手册，第I卷:用户级ISA，版本2.0"中的表18.2指定堆栈指针 sp 是寄存器 x14 .但是，说明

I'm confused about the RISC-V ABI Register Names. For example, Table 18.2 in the "RISC-V Instruction Set Manual, Volume I: User-Level ISA, Version 2.0" at page 85 specifies that the stack pointer sp is register x14. However, the instruction

addi sp,zero,0

riscv64-unknown-elf-as将

编译为0x00000113( -m32 没有区别).二进制:

is compiled to 0x00000113 by riscv64-unknown-elf-as (-m32 does not make a difference). In binary:

000000000000 00000 000 00010 0010011
^imm         ^rs1  ^f3 ^rd   ^opcode

因此，这里的 sp 似乎是 x2 .然后我在Google上搜索了一下，并找到了 RISC-V Linux用户手册.该文档指出 sp 是 x30 .

So here sp seems to be x2. Then I googled a bit and found the RISC-V Linux User's Manual. This document states that sp is x30.

那是什么?有不同的ABI吗?我可以通过命令行选项将ABI设置为 riscv64-unknown-elf-* 吗?那里有一张综合桌子吗?

So what is it? Are there different ABIs? Can I set the ABI with a command line option to riscv64-unknown-elf-*? Is there a comprehensive table somewhere?

推荐答案

堆栈指针现在为 x2 .

此处是当前的ABI文档，已从用户级ISA规范中移出，现在包含该文档.相同的链接.

Here is the current ABI documentation, which has been moved out of the User-Level ISA specification, which now contains that same link.

对ABI进行了修改，以更好地适应新的RISC-V压缩规范，该规范将x8-x15中的8个最常用的寄存器彼此相邻.

The ABI was modified to better accommodate the new RISC-V compressed spec, which puts the 8 most-used registers next to each other in x8-x15.

注意:不信任任何非riscv.org网页.Quan Nguyen在其简介中明确指出，"RISC-V Linux用户手册"用于记录移植过程，并且不能保证准确性.

Note: do not trust ANY non riscv.org webpage. Quan Nguyen makes this clear in his introduction that the "RISC-V Linux User's Manual" is for documenting the porting process and that accuracy is NOT guaranteed.

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