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SLT and SLTU instructions

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This commit is contained in:
Franco Colmenarez
2022-01-05 18:11:40 -05:00
parent f44112991a
commit ca1fc4d12c
1 changed files with 69 additions and 0 deletions
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69
src/cpu.rs
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@@ -145,6 +145,16 @@ impl CPU {
let (rd, rs, rt) = params_rd_rs_rt(opcode);
self.nor(rd, rs, rt);
},
// SLT
0b000_0010_1010 => {
let (rd, rs, rt) = params_rd_rs_rt(opcode);
self.slt(rd, rs, rt);
},
// SLTU
0b000_0010_1011 => {
let (rd, rs, rt) = params_rd_rs_rt(opcode);
self.slt(rd, rs, rt);
},
_ => unimplemented!(),
};
},
@@ -362,6 +372,16 @@ impl CPU {
let result = !(self.registers.get_by_number(rs) | self.registers.get_by_number(rt));
self.registers.set_by_number(rd, result);
}
pub fn slt(&mut self, rd: usize, rs: usize, rt: usize) {
let result = self.registers.get_by_number(rs) < self.registers.get_by_number(rt);
self.registers.set_by_number(rd, if result {1} else {0});
}
pub fn sltu(&mut self, rd: usize, rs: usize, rt: usize) {
let result = (self.registers.get_by_number(rs) as u64) < (self.registers.get_by_number(rt) as u64);
self.registers.set_by_number(rd, if result {1} else {0});
}
}
#[cfg(test)]
@@ -667,4 +687,53 @@ mod cpu_instructions_tests {
cpu.nor(reg_dest, reg_s, reg_t);
assert_eq!(cpu.registers.get_by_number(reg_dest), -380);
}
#[test]
fn test_slt() {
let mut cpu = CPU::new();
let reg_dest = 10;
let reg_s = 15;
let reg_t = 20;
cpu.registers.set_by_number(reg_s, 123);
cpu.registers.set_by_number(reg_t, 123);
cpu.slt(reg_dest, reg_s, reg_t);
assert_eq!(cpu.registers.get_by_number(reg_dest), 0);
cpu.registers.set_by_number(reg_s, 123);
cpu.registers.set_by_number(reg_t, 321);
cpu.slt(reg_dest, reg_s, reg_t);
assert_eq!(cpu.registers.get_by_number(reg_dest), 1);
cpu.registers.set_by_number(reg_s, 321);
cpu.registers.set_by_number(reg_t, 123);
cpu.slt(reg_dest, reg_s, reg_t);
assert_eq!(cpu.registers.get_by_number(reg_dest), 0);
}
#[test]
fn test_sltu() {
let mut cpu = CPU::new();
let reg_dest = 10;
let reg_s = 15;
let reg_t = 20;
cpu.registers.set_by_number(reg_s, 123);
cpu.registers.set_by_number(reg_t, 123);
cpu.sltu(reg_dest, reg_s, reg_t);
assert_eq!(cpu.registers.get_by_number(reg_dest), 0);
cpu.registers.set_by_number(reg_s, 123);
cpu.registers.set_by_number(reg_t, 321);
cpu.sltu(reg_dest, reg_s, reg_t);
assert_eq!(cpu.registers.get_by_number(reg_dest), 1);
cpu.registers.set_by_number(reg_s, 321);
cpu.registers.set_by_number(reg_t, 123);
cpu.sltu(reg_dest, reg_s, reg_t);
assert_eq!(cpu.registers.get_by_number(reg_dest), 0);
cpu.registers.set_by_number(reg_s, i64::MAX);
cpu.registers.set_by_number(reg_t, i64::MIN);
cpu.sltu(reg_dest, reg_s, reg_t);
assert_eq!(cpu.registers.get_by_number(reg_dest), 1);
}
}