From 966eb6833451371ffe42cf77d6e08ac778abf34b Mon Sep 17 00:00:00 2001
From: Nathan Lee <me@nwlee.tech>
Date: Wed, 3 Jun 2026 20:50:08 -0500
Subject: finish I set instructions

---
 src/main.rs | 27 ++++++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

(limited to 'src')

diff --git a/src/main.rs b/src/main.rs
index 8974330..ad3043d 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -241,8 +241,25 @@ fn handle_instruction(memory: &mut [u8], registers: &mut [u32], pc: &mut u32) {
                 _ => panic!("Illegal instruction: {:x}", word)
             }
         },
-        0b1101111 => println!("J-type (todo)"),
-        0b1100111 => println!("jalr"),
+        0b1101111 => {
+            let rd = (word >> 7) & 0b11111;
+            let imm = word >> 12;
+            registers[rd as usize] = *pc + 4;
+            *pc += imm;
+        }, // jal
+        0b1100111 => {
+            let rs1 = (word >> 15) & 0b11111;
+            let rd = (word >> 7) & 0b11111;
+            let imm = word >> 20;
+
+            let sentinel = (word >> 12) & 0b111;
+            if (sentinel != 0) {
+                panic!("Illegal instruction: {:x}", word);
+            }
+
+            registers[rd as usize] = *pc + 4;
+            *pc = registers[rs1 as usize] + imm;
+        },
         0b0110111 => {
             let imm = word >> 12;
             let rd = ((word >> 7) & 0b11111) as usize;
@@ -251,7 +268,7 @@ fn handle_instruction(memory: &mut [u8], registers: &mut [u32], pc: &mut u32) {
         0b0010111 => {
             let imm = word >> 12;
             let rd = (word >> 7) & 0b11111;
-            registers[rd as usize] = pc + (imm << 12); // auipc
+            registers[rd as usize] = *pc + (imm << 12); // auipc
         }
         0b1110011 => {
             // ecall
@@ -259,7 +276,7 @@ fn handle_instruction(memory: &mut [u8], registers: &mut [u32], pc: &mut u32) {
                 "TRAP! syscall {} with gp registers {:?} calling instruction {:x}",
                 registers[17],
                 &registers[10..17],
-                pc
+                *pc
             );
             if registers[17] == 0 {
                 // sys_write: just a debug
@@ -268,7 +285,7 @@ fn handle_instruction(memory: &mut [u8], registers: &mut [u32], pc: &mut u32) {
                 let total_bytes = &memory[buf..buf + len];
                 io::stdout().write(&total_bytes).unwrap();
             }
-        }
+        } // ecall (ebreak not implemented)
         _ => panic!("Illegal instruction or todo: {:x}", word),
     }
 
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