Add OP_GREATERTHANOREQUAL page

Author: thunderbiscuit

.vitepress/config.js

@@ -175,7 +175,7 @@ export default {
         { text: "<code>159 | OP_LESSTHAN</code>", link: "/opcodes/OP_LESSTHAN.md" },
         { text: "<code>160 | OP_GREATERTHAN</code>", link: "/opcodes/OP_GREATERTHAN.md" },
         { text: "<code>161 | 🚧 OP_LESSTHANOREQUAL</code>", link: "/opcodes/OP_LESSTHANOREQUAL.md" },
-        { text: "<code>162 | 🚧 OP_GREATERTHANOREQUAL</code>", link: "/opcodes/OP_GREATERTHANOREQUAL.md" },
+        { text: "<code>162 | OP_GREATERTHANOREQUAL</code>", link: "/opcodes/OP_GREATERTHANOREQUAL.md" },
         { text: "<code>163 | 🚧 OP_MIN</code>", link: "/opcodes/OP_MIN.md" },
         { text: "<code>164 | 🚧 OP_MAX</code>", link: "/opcodes/OP_MAX.md" },
         { text: "<code>165 | 🚧 OP_WITHIN</code>", link: "/opcodes/OP_WITHIN.md" },

opcodes/OP_GREATERTHANOREQUAL.md

@@ -1,5 +1,59 @@
-# Work In Progress
+# OP_GREATERTHANOREQUAL
 
-:::warning
-This page has not yet been written. If you have experience with bitcoin Script and would like to contribute, please do! You can open a PR [on the repository for this website](https://github.com/thunderbiscuit/opcode-explained).
+:::info
+**Opcode number:** 162
+**Byte representation:** `0xa2`
+**Short description:** Pop the top two items; push 1 if the second is greater than or equal to the top, 0 otherwise.
 :::
+
+`OP_GREATERTHANOREQUAL` compares the top two items on the stack as integers. If the second item is greater than or equal to the top item, it pushes 1 (true) onto the stack. If not, it pushes an empty array (false). Both items are removed from the stack after the comparison.
+
+### Operation
+1. Take the top item (a) and the second item (b) from the stack.
+2. Compare the two items:
+   - If b >= a, push 1 (true) onto the stack.
+   - Otherwise, push an empty array (false) onto the stack.
+3.	Remove the original items (a and b) from the stack.
+
+### Notes
+
+- Both items must be valid integers. Bitcoin Script interprets byte arrays up to **4 bytes** as integers.
+- An empty array (`[]`) is treated as 0 when compared.
+- If there are fewer than two items on the stack when `OP_GREATERTHAN` is executed, the script will fail.
+
+
+## Examples
+
+### Example 1: Second item is greater than the top item
+
+```shell
+# ASM script
+OP_3 OP_2 OP_GREATERTHANOREQUAL
+
+# Raw script
+5352a1
+
+# Stack (before OP_GREATERTHANOREQUAL)
+2  # top
+3
+
+# Stack (after OP_GREATERTHANOREQUAL)
+1  # true, as 3 >= 2
+```
+
+### Example 2: Second item is equal to the top item
+
+```shell
+# ASM script
+OP_2 OP_2 OP_GREATERTHANOREQUAL
+
+# Raw script
+5252a1
+
+# Stack (before OP_GREATERTHANOREQUAL)
+2  # top
+2
+
+# Stack (after OP_GREATERTHANOREQUAL)
+1  # true, as 2 >= 2
+```