Add Linux Unicorn patch + desc. (#2609)

Ryujinx.Tests.Unicorn/libs/README.md

@@ -1,3 +1,22 @@
-The pre-compiled dynamic libraries in this directory are licenced under the GPLv2.
+# Unicorn
 
-The source code for windows/unicorn.dll is available at: https://github.com/MerryMage/UnicornDotNet/tree/299451c02d9c810d2feca51f5e9cb6d8b2f38960
+Unicorn is a CPU simulator with bindings in many languages, including
+C#/.NET.
+It is used by the Ryujinx test suite for comparative testing with its built-in
+CPU simulator, Armeilleure.
+
+## Windows
+
+On Windows, Unicorn is shipped as a pre-compiled dynamic library (`.dll`), licenced under the GPLv2.
+
+The source code for `windows/unicorn.dll` is available at: https://github.com/MerryMage/UnicornDotNet/tree/299451c02d9c810d2feca51f5e9cb6d8b2f38960
+
+## Linux
+
+On Linux, you will first need to download Unicorn from https://github.com/unicorn-engine/unicorn.
+
+Then you need to patch it to expose the FSPCR register by applying `linux/unicorn_fspcr.patch` 
+
+Then, compile Unicorn from source with its `make.sh` script.
+
+See https://github.com/Ryujinx/Ryujinx/pull/1433 for details.

Ryujinx.Tests.Unicorn/libs/linux/unicorn_fspcr.patch

@@ -0,0 +1,24 @@
+diff --git a/qemu/target-arm/unicorn_arm.c b/qemu/target-arm/unicorn_arm.c
+index 5ff9ebb..d4953f4 100644
+--- a/qemu/target-arm/unicorn_arm.c
++++ b/qemu/target-arm/unicorn_arm.c
+@@ -101,6 +101,9 @@ int arm_reg_read(struct uc_struct *uc, unsigned int *regs, void **vals, int coun
+                 case UC_ARM_REG_FPEXC:
+                     *(int32_t *)value = ARM_CPU(uc, mycpu)->env.vfp.xregs[ARM_VFP_FPEXC];
+                     break;
++                case UC_ARM_REG_FPSCR:
++                    *(int32_t *)value = vfp_get_fpscr(&ARM_CPU(uc, mycpu)->env);
++                    break;
+                 case UC_ARM_REG_IPSR:
+                     *(uint32_t *)value = xpsr_read(&ARM_CPU(uc, mycpu)->env) & 0x1ff;
+                     break;
+@@ -175,6 +178,9 @@ int arm_reg_write(struct uc_struct *uc, unsigned int *regs, void* const* vals, i
+                 case UC_ARM_REG_FPEXC:
+                     ARM_CPU(uc, mycpu)->env.vfp.xregs[ARM_VFP_FPEXC] = *(int32_t *)value;
+                     break;
++                case UC_ARM_REG_FPSCR:
++                    vfp_set_fpscr(&ARM_CPU(uc, mycpu)->env, *(uint32_t *)value);
++                    break;
+                 case UC_ARM_REG_IPSR:
+                     xpsr_write(&ARM_CPU(uc, mycpu)->env, *(uint32_t *)value, 0x1ff);
+                     break;