feat(zkvms/nexus): Update SDK usage

Update according to their new methods.

3 files changed, 7 insertions, 25 deletions

diff --git a/zkvms/nexus/guest/Cargo.toml b/zkvms/nexus/guest/Cargo.toml
index 9bfbf7c..de7f745 100644
--- a/zkvms/nexus/guest/Cargo.toml
+++ b/zkvms/nexus/guest/Cargo.toml
@@ -5,7 +5,7 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
-nexus-rt = { path = "/nix/store/crj1vza7idyckr20y72ai3cv2fkc0ia8-Nexus-zkVM-unstable-2025-03-11/runtime" }
+nexus-rt = { path = "/nix/store/63pzywhap3cxlqf74wjdwxxc66w7f29w-Nexus-zkVM-unstable-2025-03-11/runtime" }
 postcard = { version = "1.0.10", default-features = false, features = ["alloc"] }
 
 wrapper_macro = { version = "0.1.0", path = "../wrapper_macro" }
diff --git a/zkvms/nexus/guest/guest.ld b/zkvms/nexus/guest/guest.ld
index 5a4dd4a..384c76c 100644
--- a/zkvms/nexus/guest/guest.ld
+++ b/zkvms/nexus/guest/guest.ld
@@ -1,14 +1,12 @@
 ENTRY(_start);
 
+/* nb: when proving we will rebuild the memory model based on the first
+       pass' usages, so there is no cost for a "suboptimal" layout here */
+
 SECTIONS
 {
-  /* Set the default size of the stack.                                                 */
-  /*                                                                                    */
-  /* Because the stack will grow down from this point, and if the heap requests memory  */
-  /* being used by the stack then the runtime will panic, this value also functions as  */
-  /* the memory limit for the guest program execution more generally.                   */
-  __memory_top = 0x6400000;
-  . = 0;
+  __memory_top = 0x80400000;
+  . = 0x1000;
 
   .text : ALIGN(4)
   {
@@ -19,7 +17,6 @@ SECTIONS
   }
 
   . = ALIGN(8);
-  . = .* 2;
 
   .data : ALIGN(4)
   {
@@ -44,14 +41,6 @@ SECTIONS
     _end = .;
   }
 
-  /* Dynamic relocations are unsupported. This section is only used to detect
-     relocatable code in the input files and raise an error if relocatable code
-     is found */
-  .got (INFO) :
-  {
-    KEEP(*(.got .got.*));
-  }
-
   /DISCARD/ :
   {
     *(.comment*)
@@ -64,10 +53,3 @@ SECTIONS
 }
 
 ASSERT(. < __memory_top, "Program is too large for the VM memory.");
-
-ASSERT(SIZEOF(.got) == 0, "
-.got section detected in the input files. Dynamic relocations are not
-supported. If you are linking to C code compiled using the `gcc` crate
-then modify your build script to compile the C code _without_ the
--fPIC flag. See the documentation of the `gcc::Config.fpic` method for
-details.");
diff --git a/zkvms/nexus/guest/src/main.rs b/zkvms/nexus/guest/src/main.rs
index fd7c1d5..75b4d7d 100644
--- a/zkvms/nexus/guest/src/main.rs
+++ b/zkvms/nexus/guest/src/main.rs
@@ -1,6 +1,6 @@
 #![cfg_attr(target_arch = "riscv32", no_std, no_main, allow(unused_imports))]
 
-use nexus_rt::{postcard, println, read_private_input, write_output};
+use nexus_rt::{postcard, println, read_private_input, write_public_output};
 
 extern crate alloc;
 use alloc::{collections::*, vec::*};