WebThis file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Volume 2 of the RISC-V ISAspecification, or “The PrivilegedSpec”, defines offered privilege levels. In simplest terms, RISC-V offers threelevels of privilege, or modes, which systems can choose to support indifferent configurations. The three basic modes include: 1. Machine (M) 2. Supervisor (S) 3. User (U) These … See more In our post on Caller and Callee SavedRegisters,we introduced 32 General Purpose Registers (GPRs) defined in the RISC-V ISA.These … See more In our Introduction to InstructionFormatspost we covered a few instructions offered by the RISC-V base ISAs, and touchedbriefly on how RISC-V uses an extension … See more As previously mentioned, our entry point is defined as start, which is ataddress 0x80000000 in memory. QEMU will jump there after some initial setup,and since we already set a breakpoint, we can issue a “continue” (c) … See more As previously mentioned, a hart starts out in Mmode. We can break out QEMU tosee this in action, but first we’ll need to write a program to step through. Inprevious posts we have written C … See more
Hardware Floating Point – Stephen Marz
WebJul 9, 2024 · asm volatile ("addi t0, t0, 0x4"); asm volatile ("csrw mepc, t0");}} In the exception handler, we need to enable the timer interrupt by set the MTIE bit in the MIE … WebApr 19, 2024 · li t0, 0x1f csrw 0xbc0, t0 /* Enable nested and hardware stack */ li t0, 0x1f csrw 0x804, ... 1 bnez a0, 1 b jal SystemInit la t0, main csrw mepc, t0 mret. 这里有一些自定义的 csr，比如 corecfgr(0xbc0)，intsyscr(0x804，设置了 HWSTKEN=1, INESTEN=1, PMTCFG=0b11, HWSTKOVEN=1)，具体参考 QingKeV4_Processor_Manual。接着代码 ... poppy playtime song free hugs
OpenSBI firmware (二）firmware/fw_base.S - 知乎 - 知乎专栏
WebIs it me or qemu broke? Here is the toy code I test..section .text.init .global _start _start: .option push .option norelax la gp, _global_pointer .option pop la sp, _stack_start la t0, main csrw mepc, t0 li t1, 0b1 << 11 csrw mstatus, t1 li t2, 0 csrw satp, t2 la ra, wfi_spin csrw mtvec, ra mret wfi_spin: wfi j wfi_spin WebNov 5, 2024 · This symbol comes from virt.lds la sp, _stack_end # Setting `mstatus` register: # 0b01 11: Machine's previous protection mode is 2 (MPP=2). li t0, 0b11 . 11 csrw … WebJun 14, 2024 · csrr t1, mstatus srli t0, t1, 13 andi t0, t0, 3 li t3, 3 bne t0, t3, 1f .set i, 0 .rept 32 save_fp %i, t5 .set i, i+1 .endr 1: Above, we read the mstatus register, shift it right 13 … poppy playtime setup 7