From 5e9cc3193c19fdd0d32bbc05c827ce752e17e5b3 Mon Sep 17 00:00:00 2001
From: Jacob Lifshay <programmerjake@gmail.com>
Date: Fri, 16 Oct 2020 16:41:12 -0700
Subject: [PATCH] add cmprb_0

---
 src/instr_models.rs | 16 ++++++++++++++++
 src/lib.rs          |  6 ++++++
 src/main.rs         | 15 +++++++++++++++
 3 files changed, 37 insertions(+)

diff --git a/src/instr_models.rs b/src/instr_models.rs
index dd8c037..069e58e 100644
--- a/src/instr_models.rs
+++ b/src/instr_models.rs
@@ -850,3 +850,19 @@ pub fn cmplw(inputs: InstructionInput) -> InstructionResult {
         ..InstructionOutput::default()
     })
 }
+
+pub fn cmprb_0(inputs: InstructionInput) -> InstructionResult {
+    let ra = inputs.try_get_ra()? as u8;
+    let rb: u64 = inputs.try_get_rb()?;
+    let eq = ra >= rb as u8 && ra <= (rb >> 8) as u8;
+    let cr0 = ConditionRegister {
+        lt: false,
+        gt: false,
+        eq,
+        so: false,
+    };
+    Ok(InstructionOutput {
+        cr0: Some(cr0),
+        ..InstructionOutput::default()
+    })
+}
diff --git a/src/lib.rs b/src/lib.rs
index 940dfde..d544724 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -837,6 +837,12 @@ instructions! {
     fn cmplw(Ra, Rb, Overflow) -> (CR0) {
         "cmplw"
     }
+
+    // cmprb 0, 0, ..., ...
+    #[enumerant = CmpRB0]
+    fn cmprb_0(Ra, Rb) -> (CR0) {
+        "cmprb 0, 0,"
+    }
 }
 
 // must be after instrs macro call since it uses a macro definition
diff --git a/src/main.rs b/src/main.rs
index bf421d6..2b48024 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -26,6 +26,21 @@ const TEST_VALUES: &[u64] = &[
     0x7FFF,
     0x8000,
     0x8001,
+    // picked for cmprb
+    0xFFED_CBA9_8765_4321,
+    // last byte of next 12 tests limits of ranges for cmprb
+    0x85AE_16A6_0C1A_0E1F,
+    0xCF24_50C7_9E7E_DF20,
+    0xD486_2724_930B_9021,
+    0xDDBA_3880_8588_DF42,
+    0x1F07_F322_68FE_5C43,
+    0x739D_46C6_1E05_AE44,
+    0xA131_E014_B201_9064,
+    0xC70D_BC09_C48A_C665,
+    0x1D61_5696_5920_E966,
+    0x70F1_F260_8938_4486,
+    0xEF25_5D74_1B45_CA87,
+    0x3C54_DFA8_C006_5688,
 ];
 
 const IMMED16_TEST_VALUES: &[u16] = &[
-- 
2.30.2