From 3695b659af12996f07d40088bf175a083770d573 Mon Sep 17 00:00:00 2001
From: Aaron Taylor <ataylor@subgeniuskitty.com>
Date: Sat, 13 Jul 2019 00:39:05 -0700
Subject: [PATCH] Added memset function to VVS stdlib.

---
 stdlib/README.md |  3 ++-
 stdlib/heap.pvvs | 61 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+), 1 deletion(-)
 create mode 100644 stdlib/heap.pvvs

diff --git a/stdlib/README.md b/stdlib/README.md
index 2bba7d5..63af366 100644
--- a/stdlib/README.md
+++ b/stdlib/README.md
@@ -33,7 +33,8 @@ header comment for each function to learn the call and return stack.
          010xxx - math functions
           10000 ----- random                        (math.pvvs)
           10001 ----- absolute value                (math.pvvs)
-         011xxx - unassigned
+         011xxx - heap functions
+          11000 ----- memset                        (heap.pvvs)
          100xxx - unassigned
          101xxx - unassigned
          110xxx - conversion functions
diff --git a/stdlib/heap.pvvs b/stdlib/heap.pvvs
new file mode 100644
index 0000000..62a0216
--- /dev/null
+++ b/stdlib/heap.pvvs
@@ -0,0 +1,61 @@
+#ifndef VVS_STDLIB_HEAP
+#define VVS_STDLIB_HEAP
+
+@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+@ Description:
+@   This function writes pattern into the memory locations:
+@     startaddr -> startaddr+numbytes
+@ Call Stack:
+@   pattern
+@   startaddr
+@   numbytes  <-- TOS
+@ Return Stack:
+@   <empty>
+@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
+NSSVTTSSSN              | Mark: 11000 (memset)
+
+@ Prepare the stack for computation.
+@ Addr | Contents
+@    0 | numbytes
+@    1 | startaddr
+@    2 | pattern
+
+SSSSN                   | PUSH 0 (ptr)
+SNT                     | SWAP
+TTS                     | STORE
+SSSTN                   | PUSH 1 (ptr)
+SNT                     | SWAP
+TTS                     | STORE
+SSSTSN                  | PUSH 2 (ptr)
+SNT                     | SWAP
+TTS                     | STORE
+
+@ Store pattern into one memory location on each pass through this loop.
+NSSVSSSTTSSSSSSSSSSSN   | Mark: 00011000 00000000
+SSSSN                   | PUSH 0 (ptr)
+TTT                     | LOAD
+SSSTN                   | PUSH 1 (ptr)
+TTT                     | LOAD
+TSSS                    | ADD
+SSSTSN                  | PUSH 2 (ptr)
+TTT                     | LOAD
+TTS                     | STORE
+
+@ Decrement and check for loop end condition numbytes == 0.
+SSSSN                   | PUSH 0 (ptr)
+TTT                     | LOAD
+SNS                     | DUP
+NTSSSSTTSSSSSSSSSSTN    | BRZ > 00011000 00000001
+SSSTN                   | PUSH 1
+TSST                    | SUBTRACT
+SSSSN                   | PUSH 0 (ptr)
+SNT                     | SWAP
+TTS                     | STORE
+NSNSSSTTSSSSSSSSSSSN    | JMP > 00011000 00000000
+
+@ Clean up and return
+NSSVSSSTTSSSSSSSSSSTN   | Mark: 00011000 00000001
+SNN                     | DROP
+NTN                     | RTS
+
+#endif
-- 
2.20.1