From 55155254134bcbbbe63a8d58289a4bc32fc75329 Mon Sep 17 00:00:00 2001
From: DiamondNether90 <diamondnether941@gmail.com>
Date: Thu, 4 Sep 2025 08:38:00 +1000
Subject: [PATCH] Add packages/math/math.grnd

Adds various math functions, implemented in pure ground.
---
 packages/math/math.grnd | 203 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 203 insertions(+)
 create mode 100644 packages/math/math.grnd

diff --git a/packages/math/math.grnd b/packages/math/math.grnd
new file mode 100644
index 0000000..95dae23
--- /dev/null
+++ b/packages/math/math.grnd
@@ -0,0 +1,203 @@
+fun -double !mod -double &in -double &modulus
+    lesser $in $modulus &store
+    not $store &store
+    if $store %downloop
+
+    lesser $in 0 &store
+    if $store %uploop
+
+    jump %end
+
+    @downloop
+    subtract $in $modulus &in
+    lesser $in $modulus &store
+    not $store &store
+    if $store %downloop
+    jump %end
+
+    @uploop
+    add $in $modulus &in
+    lesser $in 0 &store
+    if $store %uploop
+    jump %end
+
+    @end
+    return $in
+endfun
+
+fun -double !pi
+    return 3.141592653589793
+endfun
+
+fun -double !intexp -double &base -int &power
+    lesser $power 1 &store
+    set &ans 1
+    if $store %end
+
+    @loop
+        subtract $power 1 &power
+        multiply $ans $base &ans
+        lesser $power 1 &store
+        if $store %end
+        jump %loop
+
+    @end
+    return $ans
+endfun
+
+fun -int !factorial -int &in
+    set &idx $in
+    set &ans 1
+    lesser $idx 0 &store
+    if $store %error
+
+    @loop
+        equal $idx 0 &store
+        if $store %end
+        multiply $ans $idx &ans
+        subtract $idx 1 &idx
+        jump %loop
+
+    @end
+    return $ans
+
+    @error
+    divide 1 0 &store
+endfun
+
+fun -double !cos -double &in
+    # Get input modulo 2π
+    call !pi &pi
+    multiply $pi 2 &tau
+    pusharg $in
+    pusharg $tau
+    call !mod &in
+    
+    set &idx 0
+    set &ans 0
+
+    # Check if $in < π
+    greater $in $pi &store
+    if $store %cos2
+    jump %cos1
+
+    @cos1
+    # Taylor series at x=π/2
+    multiply $idx 2 &2k+1
+    add $2k+1 1 &2k+1
+    
+    # Get (x-π/2)^(2k+1)
+    divide $pi 2 &store
+    subtract $in $store &store
+    pusharg $store
+    tostring $2k+1 &2k+1
+    stoi $2k+1 &2k+1
+    pusharg $2k+1
+    call !intexp &exp
+
+    # Get (2k+1)!
+    pusharg $2k+1
+    call !factorial &fact
+
+    # Divide
+    divide $exp $fact &tempans
+
+    # Add result to $ans
+    tostring $idx &idx
+    stod $idx &idx
+    pusharg $idx
+    stod "2" &store
+    pusharg $store
+    call !mod &store
+    equal $store 0 &store
+    if $store %subtract
+    jump %add
+
+    @add
+    add $ans $tempans &ans
+    jump %increment
+
+    @subtract
+    subtract $ans $tempans &ans
+    jump %increment
+
+    @increment    
+    add $idx 1 &idx
+    equal $idx 5 &store
+    if $store %end
+    jump %cos1
+
+    @cos2
+    # cos(x)=cos(2π-x)
+    subtract $tau $in &in
+    jump %cos1
+
+    @end
+    return $ans
+endfun
+
+fun -double !sin -double &in
+    call !pi &halfpi
+    divide $halfpi 2 &halfpi
+    subtract $halfpi $in &in
+    pusharg $in
+    call !cos &store
+    return $store
+endfun
+
+fun -double !tan -double &in
+    pusharg $in
+    call !sin &store
+    pusharg $in
+    call !cos &store2
+    divide $store $store2 &store
+    return $store
+endfun
+
+fun -double !random -int &seed
+    set &m 2147483648
+    set &a 1103515245
+    set &c 12345
+    multiply $seed $a &store
+    add $store $c &store
+    tostring $store &store
+    stod $store &store
+    pusharg $store
+    pusharg $m
+    call !mod &store
+    divide $store 2147483648 &store
+    return $store
+endfun
+
+fun -double !itod -int &int
+    tostring $int &int
+    stod $int &int
+    return $int
+endfun
+
+fun -int !dtoi -double &double
+    tostring $double &double
+    stoi $double &double
+    return $double
+endfun
+
+fun -double !sqrt -double &in
+    # Finding sqrt(a) is the same as finding the roots of
+    # f(x) = x^2 - a
+    # Using Newton's method: x_(k+1) = x_k - f(x_k)/f'(x_k) = x_k - ((x_k)^2+a)/2(x_k)
+    @loop
+        multiply $ans $ans &num
+        add $ans $in &num
+
+        multiply $ans 2 &dom
+
+        divide $num $dom &store
+        equal $store 0 &store2
+        if $store2 %end
+
+        subtract $ans $store &ans
+        jump %loop
+
+    @end
+    return $ans
+endfun
\ No newline at end of file