feat: add signed memory loads

1 files changed, 12 insertions, 2 deletions

diff --git a/docs/language.md b/docs/language.md
index 4de054f..3ccdab8 100644
--- a/docs/language.md
+++ b/docs/language.md
@@ -50,7 +50,7 @@ Unknown keys, a `bits` value other than 32/64, and unknown extensions are errors
 
 ## Constants and data
 
-`const` names a constant integer expression — integer literals, character literals, other constants, and `+` `-` `*` `/`. Integers are decimal, `0x` hex, or `0b` binary (these forms work anywhere an integer does). `data` puts a string in `.data`; the name is its address and `.len` is its length in bytes.
+`const` names a constant integer expression — integer literals, character literals, other constants, a leading `-`, and `+` `-` `*` `/`. Integers are decimal, `0x` hex, or `0b` binary (these forms work anywhere an integer does). `data` puts a string in `.data`; the name is its address and `.len` is its length in bytes.
 
 ```hdass
 const STDOUT = 1
@@ -138,7 +138,7 @@ if rax > rbx
 else if rax == rbx
     rdi = 0
 else
-    rdi = 2
+    rdi = -1
 ```
 
 ## Dereference (`^`)
@@ -170,10 +170,20 @@ rcx = ^dword rsi    // mov ecx, [rsi]        (32-bit load zero-extends)
 rdx = ^rsi + 4      // load, then add 4
 ```
 
+`^signed` before the size sign-extends instead, so a narrower value keeps its sign in the full register. It needs a `byte`, `word`, or `dword` size (a full-width load has nothing to extend):
+
+```hdass
+rax = ^signed byte rsi     // movsx rax, byte [rsi]
+rbx = ^signed word rsi     // movsx rbx, word [rsi]
+rcx = ^signed dword rsi    // movsxd rcx, dword [rsi]
+```
+
 ## Expressions
 
 Assignment values and `if` operands: registers, integers, chars (`'0'`), constants, data names, member access (`data.len`), and `+` `-` `*` `/` `%`. Operators are left-associative and each right-hand operand must be a single term, so `a * b + c` works but `a + b * c` (a nested right operand) doesn't yet.
 
+A leading `-` negates a term (`rax = -5`, `rbx = rax + -3`, `const OFFSET = -8`). It only applies to values that fold to a constant, so it emits a negative immediate; negating a register (`-rbx`) is not supported.
+
 ## Extensions
 
 ### logical_registers