From cf6fac42b4404b33248a82f2baeaf6dbbb7b7dfd Mon Sep 17 00:00:00 2001
From: Rohan Fredriksson <rohan.fredriksson@gmail.com>
Date: Sun, 4 Jun 2023 22:37:02 +1000
Subject: [PATCH] Initial commit

---
 arbitrary.glsl | 12 ++++++++++++
 1 file changed, 12 insertions(+)
 create mode 100644 arbitrary.glsl

diff --git a/arbitrary.glsl b/arbitrary.glsl
new file mode 100644
index 0000000..a898899
--- /dev/null
+++ b/arbitrary.glsl
@@ -0,0 +1,12 @@
+const int PRECISION = 3;
+const int ARRAY_SIZE = (PRECISION+1);
+const float BASE = 4294967296.0;
+const uint HALF_BASE = 2147483648u;
+
+#define assign(x, y) {for(int assign_i=0;assign_i<=PRECISION;assign_i++){x[assign_i]=y[assign_i];}}
+#define zero(x) {for(int zero_i=0;zero_i<=PRECISION;zero_i++){x[zero_i]=0u;}}
+#define load(x, v) {float load_value=(v); if (load_value<0.0) {x[0]=1u; load_value*=-1.0;} else {x[0]=0u;} for(int load_i=1; load_i<=PRECISION; load_i++) {x[load_i]=uint(load_value); load_value-=x[load_i]; load_value*=BASE;}}
+#define shift(x, v) {int shift_n=(v); for(int shift_i=shift_n+1; shift_i<=PRECISION; shift_i++) {x[shift_i]=x[shift_i-shift_n];} for(int shift_i=1; shift_i<=shift_n; shift_i++) {x[shift_i]=0u;}};
+#define negate(x) {x[0]=(x[0]==0u?1u:0u);}
+#define add(a, b, r) {uint add_buffer[PRECISION+1]; bool add_pa=a[0]==0u; bool add_pb=b[0]==0u; if (add_pa==add_pb) {uint add_carry=0u; for(int add_i=PRECISION; add_i>0; add_i--) {uint add_next=0u; if(a[add_i]+b[add_i]<a[add_i]) {add_next=1u;} add_buffer[add_i]=a[add_i]+b[add_i]+add_carry; add_carry=add_next;} if(!add_pa) {add_buffer[0]=1u;} else {add_buffer[0]=0u;}} else {bool add_flip=false; for(int add_i=1; add_i<=PRECISION; add_i++) {if(b[add_i]>a[add_i]) {add_flip=true; break;} if(a[add_i]>b[add_i]) {break;}} if(add_flip) {uint add_borrow=0u; for(int add_i=PRECISION; add_i>0; add_i--) {add_buffer[add_i]=b[add_i]-a[add_i]-add_borrow; if(b[add_i]<a[add_i]+add_borrow) {add_borrow=1u;} else {add_borrow=0u;}}} else {uint add_borrow=0u; for(int add_i=PRECISION; add_i>0; add_i--) {add_buffer[add_i]=a[add_i]-b[add_i]-add_borrow; if(a[add_i]<b[add_i]+add_borrow) {add_borrow=1u;} else {add_borrow=0u;}}} if(add_pa==add_flip) {add_buffer[0]=1u;} else {add_buffer[0]=0u;}} assign(r, add_buffer);}
+#define mul(a, b, r) {uint mul_buffer[PRECISION+1]; zero(mul_buffer); uint mul_product[2*PRECISION-1]; for(int mul_i=0; mul_i<2*PRECISION-1; mul_i++) {mul_product[mul_i]=0u;} for(int mul_i=0; mul_i<PRECISION; mul_i++) {uint mul_carry=0u; for(int mul_j=0; mul_j<PRECISION; mul_j++) {uint mul_next=0; uint mul_value=a[PRECISION-mul_i]*b[PRECISION-mul_j]; if(mul_product[mul_i+mul_j]+mul_value<mul_product[mul_i+mul_j]) {mul_next++;} mul_product[mul_i+mul_j]+=mul_value; if(mul_product[mul_i+mul_j]+mul_carry<mul_product[mul_i+mul_j]) {mul_next++;} mul_product[mul_i+mul_j]+=mul_carry; uint mul_lower_a=a[PRECISION-mul_i]&0xFFFF; uint mul_upper_a=a[PRECISION-mul_i]>>16; uint mul_lower_b=b[PRECISION-mul_j]&0xFFFF; uint mul_upper_b=b[PRECISION-mul_j]>>16; uint mul_lower=mul_lower_a*mul_lower_b; uint mul_upper=mul_upper_a*mul_upper_b; uint mul_mid=mul_lower_a*mul_upper_b; mul_upper+=mul_mid>>16; mul_mid=mul_mid<<16; if(mul_lower+mul_mid<mul_lower) {mul_upper++;} mul_lower+=mul_mid; mul_mid=mul_lower_b*mul_upper_a; mul_upper+=mul_mid>>16; mul_mid=mul_mid<<16; if(mul_lower+mul_mid<mul_lower) {mul_upper++;}; mul_carry=mul_upper+mul_next;} if(mul_i+PRECISION<2*PRECISION-1) {mul_product[mul_i+PRECISION]+=mul_carry;}} if(mul_product[PRECISION-2]>=HALF_BASE) {for(int mul_i=PRECISION-1; mul_i<2*PRECISION-1; mul_i++) {if(mul_product[mul_i]+1>mul_product[mul_i]) {mul_product[mul_i]++; break;} mul_product[mul_i]++;}} for(int mul_i=0; mul_i<PRECISION; mul_i++) {mul_buffer[mul_i+1]=mul_product[2*PRECISION-2-mul_i];} if((a[0]==0u)!=(b[0]==0u)) {mul_buffer[0]=1u;}; assign(r, mul_buffer);}
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