From d1ac45feaebc9c3c2e18e9c03d363d8c4d6c9e61 Mon Sep 17 00:00:00 2001
From: d_m <d_m@plastic-idolatry.com>
Date: Fri, 2 Aug 2024 11:31:03 -0400
Subject: [PATCH] man uxntal updates

---
 uxntal.1 | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 82 insertions(+), 1 deletion(-)

diff --git a/uxntal.1 b/uxntal.1
index 601af47..e7785fa 100644
--- a/uxntal.1
+++ b/uxntal.1
@@ -86,8 +86,89 @@ Thus for regular instructions writing a "generic" effect (leaving sigils off val
 .SS OVR
 ( x y -- x y x )
 
+.SS EQU
+( x y -- x==y^ )
+
+.SS NEQ
+( x y -- x!=y^ )
+
+.SS GTH
+( x y -- x>y^ )
+
+.SS LTH
+( x y -- x<y^ )
+
+.SS JMP
+( x -- ; pc <- x )
+
+The program counter (\fIpc\fP) is unconditionally updated. When \fIx\fP is a byte, it is treated as relative (\fBpc += x\fP) and when \fIx\fP is a short it is treated as absolute (\fBpc = x\fP).
+
+.SS JCN
+( x bool^ -- ; pc <- x if bool )
+
+The program counter (\fIpc\fP) is updated when \fIbool\fP is non-zero. When \fIx\fP is a byte, it is treated as relative (\fBpc += x\fP) and when \fIx\fP is a short it is treated as absolute (\fBpc = x\fP).
+
+.SS JSR
+( x -- [pc+1*] )
+
+Store the next address to execute before unconditionally updating the program counter (\fIpc\fP). This instruction is usually used to invoke subroutines, which use the \fBJMP2r\fP to return.
+
+.SS STH
+( x -- [x] )
+
+.SS LDZ
+( zp^ -- x )
+
+Load data from a zero-page address (\fB0x0000 - 0x00ff\fP).
+
+.SS STZ
+( x zp^ -- )
+
+Store data at a zero-page address (\fB0x0000 - 0x00ff\fP).
+
+.SS LDR
+( rel^ -- x )
+
+Load data from a relative address (\fBpc + x\fP).
+
+Note that unlike \fBLDZk\fP and \fBLDAk\fP the \fBLDRk\fP instruction is not very useful, since a relative address is usually only meaningful when run from a particular address (i.e. for a particular \fBpc\fP value).
+
+
+.SS STR
+( x rel^ -- )
+
+Store data at a relative address (\fBpc + x\fP).
+
+Note that unlike \fBSTZk\fP and \fBSTAk\fP the \fBSTRk\fP instruction is not very useful, since a relative address is usually only meaningful when run from a particular address (i.e. for a particular \fBpc\fP value).
+
+.SS LDA
+( abs* -- x )
+
+Load data from an absolute address (\fB0x0000 - 0xffff\fP).
+
+.SS STA
+( x abs* -- )
+
+Store data at an absolute address (\fB0x0000 - 0xffff\fP).
+
+.SS DEI
+( dev^ -- x )
+
+Read data from a device port (\fB0x00 - 0xff\fP).
+
+Reading from some ports may have an effect on the underlying VM; in other cases it will simply read values from device memory. See Varvara device documentation for more details.
+
+.SS DEO
+( x dev^ -- )
+
+Write data to a device port (\fB0x00 - 0xff\fP).
+
+Writing to some ports may have an effect on the underlying VM; in other cases it will simply write values to device memory. See Varvara device documentation for more details.
+
 .SH SPECIAL INSTRUCTIONS
 
+These instructions do not accept all mode flags (some do not accept any).
+
 .SS BRK
 
 The break instruction is used to end a vector call and return control to the virtual machine.
@@ -98,7 +179,7 @@ The "immediate jump" instructions are produced by the assembler. They interpret
 
  \fBJMI\fP ( -- )        jump to \fIaddr\fP unconditionally
  \fBJCI\fP ( bool^ -- )  jump to \fIaddr\fP if \fIbool\fP is non-zero
- \fBJSI\fP ( -- [cur*] ) jump to \fIaddr\fP saving the current address (\fIcur\fP) on the return stack
+ \fBJSI\fP ( -- [pc*] ) jump to \fIaddr\fP saving the current address (\fIpc\fP) on the return stack
 
 (The instruction pointer will be moved forward 2 bytes, past the relative address.)