From 60a9de1246137334cfdf1385d6a131f05597ee20 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kristj=C3=A1n=20Valur=20J=C3=B3nsson?= <sweskman@gmail.com>
Date: Sun, 16 Nov 2025 17:26:19 +0000
Subject: [PATCH 01/15] Add RISC-V RV64 platform support (skeleton)

- Added platform detection for RISC-V 64-bit (__riscv && __riscv_xlen == 64)
- Created skeleton assembly implementation (switch_riscv64_gcc.S)
- Added RISC-V header file (switch_riscv64_gcc.h)
- Updated CI workflow to build and test riscv64 with QEMU
- Added riscv64 to release archives
- Uses LP64D ABI (64-bit pointers, hardware floating point)

TODO: Implement actual stack switching logic in assembly file
---
 .github/workflows/buildcommit.yml       |   7 +-
 stackman/platforms/platform.h           |   8 ++
 stackman/platforms/switch_riscv64_gcc.S | 126 ++++++++++++++++++++++++
 stackman/platforms/switch_riscv64_gcc.h |  19 ++++
 4 files changed, 159 insertions(+), 1 deletion(-)
 create mode 100644 stackman/platforms/switch_riscv64_gcc.S
 create mode 100644 stackman/platforms/switch_riscv64_gcc.h

diff --git a/.github/workflows/buildcommit.yml b/.github/workflows/buildcommit.yml
index 6dc8fd8..31f63ae 100644
--- a/.github/workflows/buildcommit.yml
+++ b/.github/workflows/buildcommit.yml
@@ -16,7 +16,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        name: [AMD64, i386, arm, aarch64]
+        name: [AMD64, i386, arm, aarch64, riscv64]
         include:
           - name: i386
             platformflags: -m32
@@ -26,6 +26,9 @@ jobs:
           - name: aarch64
             platformtools:  aarch64-linux-gnu
             emulator: qemu-aarch64
+          - name: riscv64
+            platformtools:  riscv64-linux-gnu
+            emulator: qemu-riscv64
     # name: build-linux-gnu (${{matrix.name}})
     env:
       PLATFORMFLAGS: ${{matrix.platformflags}}
@@ -156,6 +159,7 @@ jobs:
         cp -r artifacts/sysv_i386 release/lib/
         cp -r artifacts/arm32 release/lib/
         cp -r artifacts/aarch64 release/lib/
+        cp -r artifacts/riscv64 release/lib/
         cp -r artifacts/darwin_x86_64 release/lib/
         cp -r artifacts/darwin_arm64 release/lib/
         cp -r artifacts/win_x86 release/lib/
@@ -197,6 +201,7 @@ jobs:
             sysv_i386/       - Linux x86 (32-bit)
             arm32/           - Linux ARM (32-bit, AAPCS)
             aarch64/         - Linux ARM64 (AAPCS64)
+            riscv64/         - Linux RISC-V 64-bit (LP64D)
             darwin_x86_64/   - macOS x86_64 (Intel)
             darwin_arm64/    - macOS ARM64 (Apple Silicon)
             win_x86/         - Windows x86 (32-bit)
diff --git a/stackman/platforms/platform.h b/stackman/platforms/platform.h
index 007b852..daf3102 100644
--- a/stackman/platforms/platform.h
+++ b/stackman/platforms/platform.h
@@ -74,6 +74,10 @@
 #else
 #define _STACKMAN_ABI aarch64
 #endif
+#elif defined(__riscv) && (__riscv_xlen == 64)
+#include "switch_riscv64_gcc.h" /* gcc using riscv64 */
+#define _STACKMAN_PLATFORM riscv64_clang
+#define _STACKMAN_ABI riscv64
 #endif
 #endif /* __clang__ */
 
@@ -103,6 +107,10 @@
 #else
 #define _STACKMAN_ABI aarch64
 #endif
+#elif defined(__riscv) && (__riscv_xlen == 64)
+#include "switch_riscv64_gcc.h" /* gcc using riscv64 */
+#define _STACKMAN_PLATFORM riscv64_gcc
+#define _STACKMAN_ABI riscv64
 #endif
 #endif /* __GNUC__ */
 
diff --git a/stackman/platforms/switch_riscv64_gcc.S b/stackman/platforms/switch_riscv64_gcc.S
new file mode 100644
index 0000000..a4d40b2
--- /dev/null
+++ b/stackman/platforms/switch_riscv64_gcc.S
@@ -0,0 +1,126 @@
+/*
+ * RISC-V RV64 (LP64D ABI) stack switching implementation
+ * 
+ * This file provides stack manipulation for RISC-V 64-bit (RV64) using the
+ * LP64D ABI (64-bit pointers, hardware double-precision floating point).
+ * 
+ * RISC-V RV64 LP64D Calling Convention:
+ * - Arguments: a0-a7 (x10-x17)
+ * - Return: a0-a1 (x10-x11)
+ * - Callee-saved: s0-s11 (x8-x9, x18-x27), sp (x2)
+ * - Caller-saved: a0-a7, t0-t6, ra (x1)
+ * - Stack pointer: sp (x2) - must be 16-byte aligned
+ * - Frame pointer: s0/fp (x8) - optional
+ */
+
+/* ELF metadata and CFI directives */
+#define FUNCTION(name) .globl name ; .type name, @function
+#define LABEL(name) name:
+#define TYPE_FUNCTION(name) .type name, @function
+#define SIZE_FUNCTION(name) .size name, .-name
+#define GNU_STACK .section .note.GNU-stack,"",@progbits
+#define CFI_STARTPROC .cfi_startproc
+#define CFI_ENDPROC .cfi_endproc
+#define CFI_DEF_CFA_OFFSET(x) .cfi_def_cfa_offset x
+#define CFI_OFFSET(r,o) .cfi_offset r, o
+#define CFI_RESTORE(r) .cfi_restore r
+
+	.file	"switch_riscv64_gcc.S"
+	.text
+	.align	1
+
+/* 
+ * void *stackman_switch(stackman_cb_t callback, void *context)
+ * 
+ * Saves current stack state, calls callback twice with stack pointer,
+ * and switches to new stack returned by first callback invocation.
+ * 
+ * Register usage:
+ * - a0: callback function pointer (first arg)
+ * - a1: context pointer (second arg)
+ * - Callee-saved regs: s0-s11 must be preserved
+ */
+	FUNCTION(stackman_switch)
+LABEL(stackman_switch)
+.LFB0:
+	CFI_STARTPROC
+
+	/* TODO: Calculate frame size based on saved registers
+	 * Need to save:
+	 * - ra (return address)
+	 * - s0-s11 (callee-saved registers)
+	 * - fp/s0 for frame pointer
+	 * 
+	 * Total: ~14 registers * 8 bytes = 112 bytes (round to 128 for alignment)
+	 */
+
+	/* TODO: Allocate stack frame and save registers */
+	/* addi sp, sp, -128 */
+	/* sd ra, 120(sp) */
+	/* sd s0, 112(sp) */
+	/* sd s1-s11, ... */
+
+	/* TODO: Set up frame pointer */
+	/* addi s0, sp, 128 */
+
+	/* TODO: Call callback with current sp */
+	/* First call: callback(context, sp) */
+	/* mv a1, sp          # second arg = current sp */
+	/* mv a2, a0          # save callback for later */
+	/* mv a0, a1_original # first arg = context */
+	/* jalr a2            # call callback */
+
+	/* TODO: Switch to new stack returned in a0 */
+	/* mv sp, a0 */
+
+	/* TODO: Second callback invocation with new sp */
+	/* Same pattern as first call */
+
+	/* TODO: Restore registers from new stack */
+	/* ld s11, offset(sp) */
+	/* ... */
+	/* ld ra, offset(sp) */
+
+	/* TODO: Deallocate frame and return */
+	/* addi sp, sp, 128 */
+	/* ret */
+
+	/* PLACEHOLDER - just return for now */
+	ret
+
+	CFI_ENDPROC
+.LFE0:
+	SIZE_FUNCTION(stackman_switch)
+
+/* 
+ * void *stackman_call(stackman_cb_t callback, void *context, void *new_stack)
+ * 
+ * Similar to stackman_switch but uses explicitly provided stack pointer.
+ * 
+ * Register usage:
+ * - a0: callback function pointer
+ * - a1: context pointer
+ * - a2: new stack pointer
+ */
+	.align	1
+	FUNCTION(stackman_call)
+LABEL(stackman_call)
+.LFB1:
+	CFI_STARTPROC
+
+	/* TODO: Similar to stackman_switch but simpler
+	 * - Save minimal state on current stack
+	 * - Switch to new_stack (a2)
+	 * - Call callback
+	 * - Return
+	 */
+
+	/* PLACEHOLDER */
+	ret
+
+	CFI_ENDPROC
+.LFE1:
+	SIZE_FUNCTION(stackman_call)
+
+/* Mark stack as non-executable */
+GNU_STACK
diff --git a/stackman/platforms/switch_riscv64_gcc.h b/stackman/platforms/switch_riscv64_gcc.h
new file mode 100644
index 0000000..036c414
--- /dev/null
+++ b/stackman/platforms/switch_riscv64_gcc.h
@@ -0,0 +1,19 @@
+/*
+ * RISC-V RV64 (LP64D ABI) stack switching - GCC implementation
+ * 
+ * This implementation uses separate assembly files (.S) for RISC-V 64-bit.
+ * The LP64D ABI is used: 64-bit pointers with hardware floating point.
+ */
+
+#ifndef STACKMAN_SWITCH_IMPL
+/* Just check if platform is supported */
+#define STACKMAN_SWITCH_INCLUDED
+#else
+
+/* Stack pointer alignment for RISC-V - must be 16-byte aligned */
+#define STACKMAN_SP_ALIGN_BYTES 16
+
+/* Use assembly source file */
+#define STACKMAN_ASSEMBLY_SRC "stackman/platforms/switch_riscv64_gcc.S"
+
+#endif /* STACKMAN_SWITCH_IMPL */

From f5577d322e78835d3ad672548c83c635e8add723 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kristj=C3=A1n=20Valur=20J=C3=B3nsson?= <sweskman@gmail.com>
Date: Sun, 16 Nov 2025 17:51:04 +0000
Subject: [PATCH 02/15] Add dedicated RISC-V test workflow

- Triggers on push to riscv-support branch
- Installs RISC-V toolchain and QEMU
- Builds and tests riscv64 platform only
- Fast feedback for RISC-V development
---
 .github/workflows/riscv-test.yml | 52 ++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)
 create mode 100644 .github/workflows/riscv-test.yml

diff --git a/.github/workflows/riscv-test.yml b/.github/workflows/riscv-test.yml
new file mode 100644
index 0000000..3981c66
--- /dev/null
+++ b/.github/workflows/riscv-test.yml
@@ -0,0 +1,52 @@
+name: RISC-V Test Build
+
+on:
+  push:
+    branches: [ riscv-support ]
+  pull_request:
+    branches: [ master ]
+    paths:
+      - 'stackman/platforms/switch_riscv64_gcc.*'
+      - 'stackman/platforms/platform.h'
+      - '.github/workflows/riscv-test.yml'
+
+jobs:
+
+  build-riscv64:
+    runs-on: ubuntu-latest
+    
+    steps:
+    - uses: actions/checkout@v4
+    
+    - name: Install RISC-V toolchain and QEMU
+      run: |
+        sudo apt-get update
+        sudo apt-get install --no-install-recommends -y \
+          gcc-riscv64-linux-gnu \
+          g++-riscv64-linux-gnu \
+          qemu-user
+    
+    - name: Show toolchain info
+      run: |
+        riscv64-linux-gnu-gcc --version
+        qemu-riscv64 --version
+    
+    - name: Build library
+      env:
+        PLATFORM_PREFIX: riscv64-linux-gnu-
+      run: make all
+    
+    - name: Show ABI name
+      run: make abiname
+    
+    - name: Run tests
+      env:
+        PLATFORM_PREFIX: riscv64-linux-gnu-
+        EMULATOR: qemu-riscv64
+      run: make test
+    
+    - name: Upload library artifact
+      uses: actions/upload-artifact@v4
+      with:
+        name: riscv64-test-build
+        path: lib/riscv64/libstackman.a

From b08b795ba02e940eec7ee80bbfc62a7352db9eb4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kristj=C3=A1n=20Valur=20J=C3=B3nsson?= <sweskman@gmail.com>
Date: Sun, 16 Nov 2025 17:53:27 +0000
Subject: [PATCH 03/15] Fix PLATFORM_PREFIX in RISC-V workflow - remove
 trailing dash

The Makefile adds the dash automatically, so PLATFORM_PREFIX should be
'riscv64-linux-gnu' not 'riscv64-linux-gnu-'
---
 .github/workflows/riscv-test.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/riscv-test.yml b/.github/workflows/riscv-test.yml
index 3981c66..f8d7805 100644
--- a/.github/workflows/riscv-test.yml
+++ b/.github/workflows/riscv-test.yml
@@ -33,7 +33,7 @@ jobs:
     
     - name: Build library
       env:
-        PLATFORM_PREFIX: riscv64-linux-gnu-
+        PLATFORM_PREFIX: riscv64-linux-gnu
       run: make all
     
     - name: Show ABI name
@@ -41,7 +41,7 @@ jobs:
     
     - name: Run tests
       env:
-        PLATFORM_PREFIX: riscv64-linux-gnu-
+        PLATFORM_PREFIX: riscv64-linux-gnu
         EMULATOR: qemu-riscv64
       run: make test
     

From 7e07e18ef9500ee69b783e704a9af04e9acb59c5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kristj=C3=A1n=20Valur=20J=C3=B3nsson?= <sweskman@gmail.com>
Date: Sun, 16 Nov 2025 17:55:44 +0000
Subject: [PATCH 04/15] Implement RISC-V stack switching functions

- Implement stackman_switch with full register save/restore
- Implement stackman_call with minimal frame
- Save/restore callee-saved registers: s0-s11, fs0-fs11, ra
- Follow RISC-V LP64D calling convention
- Based on ARM64 implementation pattern
---
 stackman/platforms/switch_riscv64_gcc.S | 202 ++++++++++++++++++------
 1 file changed, 154 insertions(+), 48 deletions(-)

diff --git a/stackman/platforms/switch_riscv64_gcc.S b/stackman/platforms/switch_riscv64_gcc.S
index a4d40b2..7e7a770 100644
--- a/stackman/platforms/switch_riscv64_gcc.S
+++ b/stackman/platforms/switch_riscv64_gcc.S
@@ -39,53 +39,127 @@
  * - a0: callback function pointer (first arg)
  * - a1: context pointer (second arg)
  * - Callee-saved regs: s0-s11 must be preserved
+ * - FP regs: fs0-fs11 (callee-saved floating point)
  */
 	FUNCTION(stackman_switch)
 LABEL(stackman_switch)
 .LFB0:
 	CFI_STARTPROC
 
-	/* TODO: Calculate frame size based on saved registers
-	 * Need to save:
-	 * - ra (return address)
-	 * - s0-s11 (callee-saved registers)
-	 * - fp/s0 for frame pointer
-	 * 
-	 * Total: ~14 registers * 8 bytes = 112 bytes (round to 128 for alignment)
+	/* Allocate stack frame (160 bytes)
+	 * Layout: ra(8) + s0-s11(12*8=96) + fs0-fs11(12*8=96) = 200 bytes
+	 * Round to 208 for 16-byte alignment
 	 */
-
-	/* TODO: Allocate stack frame and save registers */
-	/* addi sp, sp, -128 */
-	/* sd ra, 120(sp) */
-	/* sd s0, 112(sp) */
-	/* sd s1-s11, ... */
-
-	/* TODO: Set up frame pointer */
-	/* addi s0, sp, 128 */
-
-	/* TODO: Call callback with current sp */
-	/* First call: callback(context, sp) */
-	/* mv a1, sp          # second arg = current sp */
-	/* mv a2, a0          # save callback for later */
-	/* mv a0, a1_original # first arg = context */
-	/* jalr a2            # call callback */
-
-	/* TODO: Switch to new stack returned in a0 */
-	/* mv sp, a0 */
-
-	/* TODO: Second callback invocation with new sp */
-	/* Same pattern as first call */
-
-	/* TODO: Restore registers from new stack */
-	/* ld s11, offset(sp) */
-	/* ... */
-	/* ld ra, offset(sp) */
-
-	/* TODO: Deallocate frame and return */
-	/* addi sp, sp, 128 */
-	/* ret */
-
-	/* PLACEHOLDER - just return for now */
+	addi	sp, sp, -208
+	CFI_DEF_CFA_OFFSET(208)
+	
+	/* Save return address and callee-saved registers */
+	sd	ra, 200(sp)
+	CFI_OFFSET(1, -8)	/* ra is x1 */
+	sd	s0, 192(sp)
+	CFI_OFFSET(8, -16)
+	sd	s1, 184(sp)
+	CFI_OFFSET(9, -24)
+	sd	s2, 176(sp)
+	CFI_OFFSET(18, -32)
+	sd	s3, 168(sp)
+	CFI_OFFSET(19, -40)
+	sd	s4, 160(sp)
+	CFI_OFFSET(20, -48)
+	sd	s5, 152(sp)
+	CFI_OFFSET(21, -56)
+	sd	s6, 144(sp)
+	CFI_OFFSET(22, -64)
+	sd	s7, 136(sp)
+	CFI_OFFSET(23, -72)
+	sd	s8, 128(sp)
+	CFI_OFFSET(24, -80)
+	sd	s9, 120(sp)
+	CFI_OFFSET(25, -88)
+	sd	s10, 112(sp)
+	CFI_OFFSET(26, -96)
+	sd	s11, 104(sp)
+	CFI_OFFSET(27, -104)
+	
+	/* Save callee-saved floating point registers */
+	fsd	fs0, 96(sp)
+	fsd	fs1, 88(sp)
+	fsd	fs2, 80(sp)
+	fsd	fs3, 72(sp)
+	fsd	fs4, 64(sp)
+	fsd	fs5, 56(sp)
+	fsd	fs6, 48(sp)
+	fsd	fs7, 40(sp)
+	fsd	fs8, 32(sp)
+	fsd	fs9, 24(sp)
+	fsd	fs10, 16(sp)
+	fsd	fs11, 8(sp)
+	
+	/* Preserve callback and context in callee-saved registers */
+	mv	s2, a0		/* s2 = callback */
+	mv	s3, a1		/* s3 = context */
+	
+	/* First callback: callback(context, sp, 0) */
+	mv	a0, s3		/* a0 = context */
+	mv	a1, sp		/* a1 = current sp */
+	li	a2, 0		/* a2 = 0 (first call) */
+	jalr	s2		/* call callback */
+	
+	/* Save returned pointer and switch stack */
+	mv	s4, a0		/* s4 = returned value */
+	mv	sp, a0		/* switch to new stack */
+	
+	/* Second callback: callback(context, new_sp, 1) */
+	mv	a0, s3		/* a0 = context */
+	mv	a1, sp		/* a1 = new sp */
+	li	a2, 1		/* a2 = 1 (second call) */
+	jalr	s2		/* call callback */
+	
+	/* Restore callee-saved floating point registers */
+	fld	fs11, 8(sp)
+	fld	fs10, 16(sp)
+	fld	fs9, 24(sp)
+	fld	fs8, 32(sp)
+	fld	fs7, 40(sp)
+	fld	fs6, 48(sp)
+	fld	fs5, 56(sp)
+	fld	fs4, 64(sp)
+	fld	fs3, 72(sp)
+	fld	fs2, 80(sp)
+	fld	fs1, 88(sp)
+	fld	fs0, 96(sp)
+	
+	/* Restore callee-saved integer registers */
+	ld	s11, 104(sp)
+	CFI_RESTORE(27)
+	ld	s10, 112(sp)
+	CFI_RESTORE(26)
+	ld	s9, 120(sp)
+	CFI_RESTORE(25)
+	ld	s8, 128(sp)
+	CFI_RESTORE(24)
+	ld	s7, 136(sp)
+	CFI_RESTORE(23)
+	ld	s6, 144(sp)
+	CFI_RESTORE(22)
+	ld	s5, 152(sp)
+	CFI_RESTORE(21)
+	ld	s4, 160(sp)
+	CFI_RESTORE(20)
+	ld	s3, 168(sp)
+	CFI_RESTORE(19)
+	ld	s2, 176(sp)
+	CFI_RESTORE(18)
+	ld	s1, 184(sp)
+	CFI_RESTORE(9)
+	ld	s0, 192(sp)
+	CFI_RESTORE(8)
+	ld	ra, 200(sp)
+	CFI_RESTORE(1)
+	
+	/* Deallocate frame and return */
+	addi	sp, sp, 208
+	CFI_DEF_CFA_OFFSET(0)
 	ret
 
 	CFI_ENDPROC
@@ -108,14 +182,46 @@ LABEL(stackman_call)
 .LFB1:
 	CFI_STARTPROC
 
-	/* TODO: Similar to stackman_switch but simpler
-	 * - Save minimal state on current stack
-	 * - Switch to new_stack (a2)
-	 * - Call callback
-	 * - Return
-	 */
-
-	/* PLACEHOLDER */
+	/* Allocate small frame (32 bytes for ra + s0-s2) */
+	addi	sp, sp, -32
+	CFI_DEF_CFA_OFFSET(32)
+	
+	/* Save return address and callee-saved registers we'll use */
+	sd	ra, 24(sp)
+	CFI_OFFSET(1, -8)
+	sd	s0, 16(sp)
+	CFI_OFFSET(8, -16)
+	sd	s1, 8(sp)
+	CFI_OFFSET(9, -24)
+	sd	s2, 0(sp)
+	CFI_OFFSET(18, -32)
+	
+	/* Preserve callback and context */
+	mv	s0, a0		/* s0 = callback */
+	mv	s1, a1		/* s1 = context */
+	mv	s2, a2		/* s2 = new_stack */
+	
+	/* Switch to new stack */
+	mv	sp, s2
+	
+	/* Call callback(context, new_stack, 0) */
+	mv	a0, s1		/* a0 = context */
+	mv	a1, s2		/* a1 = new_stack */
+	li	a2, 0		/* a2 = 0 */
+	jalr	s0		/* call callback */
+	
+	/* Restore registers and return */
+	ld	s2, 0(sp)
+	CFI_RESTORE(18)
+	ld	s1, 8(sp)
+	CFI_RESTORE(9)
+	ld	s0, 16(sp)
+	CFI_RESTORE(8)
+	ld	ra, 24(sp)
+	CFI_RESTORE(1)
+	
+	addi	sp, sp, 32
+	CFI_DEF_CFA_OFFSET(0)
 	ret
 
 	CFI_ENDPROC

From a5d8589c7916647b356db1d6d6519a0b634e40c2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kristj=C3=A1n=20Valur=20J=C3=B3nsson?= <sweskman@gmail.com>
Date: Sun, 16 Nov 2025 18:05:29 +0000
Subject: [PATCH 05/15] Fix stackman_call to restore original stack pointer

Critical bug fix: Save old stack pointer in s2 before switching stacks,
then restore it after callback returns. Previously tried to restore
registers from the new stack where they were never saved.
---
 stackman/platforms/switch_riscv64_gcc.S | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/stackman/platforms/switch_riscv64_gcc.S b/stackman/platforms/switch_riscv64_gcc.S
index 7e7a770..d7120c3 100644
--- a/stackman/platforms/switch_riscv64_gcc.S
+++ b/stackman/platforms/switch_riscv64_gcc.S
@@ -196,20 +196,23 @@ LABEL(stackman_call)
 	sd	s2, 0(sp)
 	CFI_OFFSET(18, -32)
 	
-	/* Preserve callback and context */
+	/* Preserve callback, context, and OLD stack pointer */
 	mv	s0, a0		/* s0 = callback */
 	mv	s1, a1		/* s1 = context */
-	mv	s2, a2		/* s2 = new_stack */
+	mv	s2, sp		/* s2 = old stack pointer (IMPORTANT!) */
 	
 	/* Switch to new stack */
-	mv	sp, s2
+	mv	sp, a2		/* sp = new_stack */
 	
 	/* Call callback(context, new_stack, 0) */
 	mv	a0, s1		/* a0 = context */
-	mv	a1, s2		/* a1 = new_stack */
+	mv	a1, a2		/* a1 = new_stack */
 	li	a2, 0		/* a2 = 0 */
 	jalr	s0		/* call callback */
 	
+	/* Restore old stack pointer */
+	mv	sp, s2
+	
 	/* Restore registers and return */
 	ld	s2, 0(sp)
 	CFI_RESTORE(18)

From 55388da605f449d5270eeb859c68fd7bea639db8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kristj=C3=A1n=20Valur=20J=C3=B3nsson?= <sweskman@gmail.com>
Date: Sun, 16 Nov 2025 18:07:41 +0000
Subject: [PATCH 06/15] Simplify stackman_call - only preserve old stack
 pointer

No need to preserve callback and context in callee-saved registers
since they're used immediately. Only need to save old sp and ra.
Reduced frame from 32 to 16 bytes.
---
 stackman/platforms/switch_riscv64_gcc.S | 57 +++++++++++--------------
 1 file changed, 24 insertions(+), 33 deletions(-)

diff --git a/stackman/platforms/switch_riscv64_gcc.S b/stackman/platforms/switch_riscv64_gcc.S
index d7120c3..c5968b2 100644
--- a/stackman/platforms/switch_riscv64_gcc.S
+++ b/stackman/platforms/switch_riscv64_gcc.S
@@ -182,53 +182,44 @@ LABEL(stackman_call)
 .LFB1:
 	CFI_STARTPROC
 
-	/* Allocate small frame (32 bytes for ra + s0-s2) */
-	addi	sp, sp, -32
-	CFI_DEF_CFA_OFFSET(32)
+	/* Allocate small frame (16 bytes for ra + old_sp) */
+	addi	sp, sp, -16
+	CFI_DEF_CFA_OFFSET(16)
 	
-	/* Save return address and callee-saved registers we'll use */
-	sd	ra, 24(sp)
+	/* Save return address and old stack pointer */
+	sd	ra, 8(sp)
 	CFI_OFFSET(1, -8)
-	sd	s0, 16(sp)
-	CFI_OFFSET(8, -16)
-	sd	s1, 8(sp)
-	CFI_OFFSET(9, -24)
-	sd	s2, 0(sp)
-	CFI_OFFSET(18, -32)
+	sd	sp, 0(sp)		/* Save old sp before we modify it */
+	CFI_OFFSET(2, -16)
 	
-	/* Preserve callback, context, and OLD stack pointer */
-	mv	s0, a0		/* s0 = callback */
-	mv	s1, a1		/* s1 = context */
-	mv	s2, sp		/* s2 = old stack pointer (IMPORTANT!) */
-	
-	/* Switch to new stack */
-	mv	sp, a2		/* sp = new_stack */
+	/* Setup args and switch to new stack
+	 * a0 already contains callback
+	 * a1 already contains context
+	 * a2 contains new_stack
+	 */
+	mv	t0, a0			/* t0 = callback (temporary) */
+	mv	t1, a2			/* t1 = new_stack (for arg) */
+	mv	sp, a2			/* switch to new stack */
 	
 	/* Call callback(context, new_stack, 0) */
-	mv	a0, s1		/* a0 = context */
-	mv	a1, a2		/* a1 = new_stack */
-	li	a2, 0		/* a2 = 0 */
-	jalr	s0		/* call callback */
+	mv	a0, a1			/* a0 = context (was in a1) */
+	mv	a1, t1			/* a1 = new_stack */
+	li	a2, 0			/* a2 = 0 */
+	jalr	t0			/* call callback */
 	
 	/* Restore old stack pointer */
-	mv	sp, s2
+	ld	sp, 0(sp)		/* Restore original sp */
 	
-	/* Restore registers and return */
-	ld	s2, 0(sp)
-	CFI_RESTORE(18)
-	ld	s1, 8(sp)
-	CFI_RESTORE(9)
-	ld	s0, 16(sp)
-	CFI_RESTORE(8)
-	ld	ra, 24(sp)
+	/* Restore return address and return */
+	ld	ra, 8(sp)
 	CFI_RESTORE(1)
 	
-	addi	sp, sp, 32
+	addi	sp, sp, 16
 	CFI_DEF_CFA_OFFSET(0)
 	ret
 
 	CFI_ENDPROC
-.LFE1:
+.LFB1:
 	SIZE_FUNCTION(stackman_call)
 
 /* Mark stack as non-executable */

From 85671e878ce50efb5be1b6b4695b7eb9d7d5bc51 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kristj=C3=A1n=20Valur=20J=C3=B3nsson?= <sweskman@gmail.com>
Date: Sun, 16 Nov 2025 18:10:02 +0000
Subject: [PATCH 07/15] Fix stackman_call to use callee-saved register for old
 sp

CRITICAL FIX: Must save old stack pointer in s0 (callee-saved register),
not on the stack. After switching to new stack, can't access old stack
memory. The callback won't clobber s0, so it's safe across the call.
---
 stackman/platforms/switch_riscv64_gcc.S | 29 +++++++++++++------------
 1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/stackman/platforms/switch_riscv64_gcc.S b/stackman/platforms/switch_riscv64_gcc.S
index c5968b2..3aab452 100644
--- a/stackman/platforms/switch_riscv64_gcc.S
+++ b/stackman/platforms/switch_riscv64_gcc.S
@@ -182,35 +182,36 @@ LABEL(stackman_call)
 .LFB1:
 	CFI_STARTPROC
 
-	/* Allocate small frame (16 bytes for ra + old_sp) */
+	/* Allocate frame for ra and s0 (callee-saved) */
 	addi	sp, sp, -16
 	CFI_DEF_CFA_OFFSET(16)
 	
-	/* Save return address and old stack pointer */
+	/* Save return address and s0 (we'll use it to preserve old sp) */
 	sd	ra, 8(sp)
 	CFI_OFFSET(1, -8)
-	sd	sp, 0(sp)		/* Save old sp before we modify it */
-	CFI_OFFSET(2, -16)
+	sd	s0, 0(sp)
+	CFI_OFFSET(8, -16)
 	
-	/* Setup args and switch to new stack
-	 * a0 already contains callback
-	 * a1 already contains context
-	 * a2 contains new_stack
-	 */
-	mv	t0, a0			/* t0 = callback (temporary) */
+	/* Save old stack pointer in s0 (callee-saved register) */
+	mv	s0, sp
+	
+	/* Setup args for callback and switch to new stack */
+	mv	t0, a0			/* t0 = callback */
 	mv	t1, a2			/* t1 = new_stack (for arg) */
 	mv	sp, a2			/* switch to new stack */
 	
 	/* Call callback(context, new_stack, 0) */
-	mv	a0, a1			/* a0 = context (was in a1) */
+	mv	a0, a1			/* a0 = context */
 	mv	a1, t1			/* a1 = new_stack */
 	li	a2, 0			/* a2 = 0 */
 	jalr	t0			/* call callback */
 	
-	/* Restore old stack pointer */
-	ld	sp, 0(sp)		/* Restore original sp */
+	/* Restore old stack pointer from s0 */
+	mv	sp, s0
 	
-	/* Restore return address and return */
+	/* Restore s0 and return address */
+	ld	s0, 0(sp)
+	CFI_RESTORE(8)
 	ld	ra, 8(sp)
 	CFI_RESTORE(1)
 	

From 96c5b8a11025959221ec4138dc3714485b76be55 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kristj=C3=A1n=20Valur=20J=C3=B3nsson?= <sweskman@gmail.com>
Date: Sun, 16 Nov 2025 18:18:27 +0000
Subject: [PATCH 08/15] Fix RISC-V header to properly include assembly source

Added __ASSEMBLER__ check and proper assembly source inclusion,
following the pattern used in ARM64. This ensures the assembly
file is actually compiled into the object file.
---
 stackman/platforms/switch_riscv64_gcc.h | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/stackman/platforms/switch_riscv64_gcc.h b/stackman/platforms/switch_riscv64_gcc.h
index 036c414..d5ccb67 100644
--- a/stackman/platforms/switch_riscv64_gcc.h
+++ b/stackman/platforms/switch_riscv64_gcc.h
@@ -13,7 +13,19 @@
 /* Stack pointer alignment for RISC-V - must be 16-byte aligned */
 #define STACKMAN_SP_ALIGN_BYTES 16
 
-/* Use assembly source file */
-#define STACKMAN_ASSEMBLY_SRC "stackman/platforms/switch_riscv64_gcc.S"
+/* Always use assembly source file for RISC-V */
+#ifndef STACKMAN_ASSEMBLY_SRC
+#define STACKMAN_ASSEMBLY_SRC "platforms/switch_riscv64_gcc.S"
+#endif
+
+#ifndef STACKMAN_HAVE_CALL
+#define STACKMAN_HAVE_CALL 1
+#define STACKMAN_STACK_ALIGN 16
+#endif
+
+#if __ASSEMBLER__ && defined(STACKMAN_ASSEMBLY_SRC)
+/* Include pre-generated assembly code */
+#include STACKMAN_ASSEMBLY_SRC
+#endif
 
 #endif /* STACKMAN_SWITCH_IMPL */

From 128e40405d25dabeb3eaa78cd458059866049c06 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kristj=C3=A1n=20Valur=20J=C3=B3nsson?= <sweskman@gmail.com>
Date: Sun, 16 Nov 2025 18:23:37 +0000
Subject: [PATCH 09/15] Remove incorrect STACKMAN_SP_ALIGN_BYTES macro

Should only use STACKMAN_STACK_ALIGN like all other platforms.
---
 stackman/platforms/switch_riscv64_gcc.h | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/stackman/platforms/switch_riscv64_gcc.h b/stackman/platforms/switch_riscv64_gcc.h
index d5ccb67..f665d35 100644
--- a/stackman/platforms/switch_riscv64_gcc.h
+++ b/stackman/platforms/switch_riscv64_gcc.h
@@ -10,9 +10,6 @@
 #define STACKMAN_SWITCH_INCLUDED
 #else
 
-/* Stack pointer alignment for RISC-V - must be 16-byte aligned */
-#define STACKMAN_SP_ALIGN_BYTES 16
-
 /* Always use assembly source file for RISC-V */
 #ifndef STACKMAN_ASSEMBLY_SRC
 #define STACKMAN_ASSEMBLY_SRC "platforms/switch_riscv64_gcc.S"

From b65bd5f68324257319975280733e1224a045959b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kristj=C3=A1n=20Valur=20J=C3=B3nsson?= <sweskman@gmail.com>
Date: Sun, 16 Nov 2025 18:25:59 +0000
Subject: [PATCH 10/15] Fix duplicate .LFB1 label in stackman_call

Should be .LFE1 (function end) not .LFB1 (function begin).
---
 stackman/platforms/switch_riscv64_gcc.S | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/stackman/platforms/switch_riscv64_gcc.S b/stackman/platforms/switch_riscv64_gcc.S
index 3aab452..8f990c7 100644
--- a/stackman/platforms/switch_riscv64_gcc.S
+++ b/stackman/platforms/switch_riscv64_gcc.S
@@ -220,7 +220,7 @@ LABEL(stackman_call)
 	ret
 
 	CFI_ENDPROC
-.LFB1:
+.LFE1:
 	SIZE_FUNCTION(stackman_call)
 
 /* Mark stack as non-executable */

From 2f23aae3999fc14edc11c0d672949b9aec014e1d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kristj=C3=A1n=20Valur=20J=C3=B3nsson?= <sweskman@gmail.com>
Date: Sun, 16 Nov 2025 18:30:38 +0000
Subject: [PATCH 11/15] Fix RISC-V header for test_static compilation

- Move STACKMAN_ASSEMBLY_SRC definition outside STACKMAN_SWITCH_IMPL
  so it's always defined (prevents inline asm fallback)
- Add #undef before redefining STACKMAN_STACK_ALIGN to avoid warning
---
 stackman/platforms/switch_riscv64_gcc.h | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/stackman/platforms/switch_riscv64_gcc.h b/stackman/platforms/switch_riscv64_gcc.h
index f665d35..8e08597 100644
--- a/stackman/platforms/switch_riscv64_gcc.h
+++ b/stackman/platforms/switch_riscv64_gcc.h
@@ -5,18 +5,19 @@
  * The LP64D ABI is used: 64-bit pointers with hardware floating point.
  */
 
+/* Always use assembly source file for RISC-V */
+#if !defined(STACKMAN_ASSEMBLY_SRC)
+#define STACKMAN_ASSEMBLY_SRC "platforms/switch_riscv64_gcc.S"
+#endif
+
 #ifndef STACKMAN_SWITCH_IMPL
 /* Just check if platform is supported */
 #define STACKMAN_SWITCH_INCLUDED
 #else
 
-/* Always use assembly source file for RISC-V */
-#ifndef STACKMAN_ASSEMBLY_SRC
-#define STACKMAN_ASSEMBLY_SRC "platforms/switch_riscv64_gcc.S"
-#endif
-
 #ifndef STACKMAN_HAVE_CALL
 #define STACKMAN_HAVE_CALL 1
+#undef STACKMAN_STACK_ALIGN
 #define STACKMAN_STACK_ALIGN 16
 #endif
 

From ac97814cf24e62c3436051a67b2cfb18b983d970 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kristj=C3=A1n=20Valur=20J=C3=B3nsson?= <sweskman@gmail.com>
Date: Sun, 16 Nov 2025 18:34:57 +0000
Subject: [PATCH 12/15] Fix callback argument order in RISC-V implementation

Callback signature is: callback(context, opcode, sp)
Was incorrectly calling: callback(context, sp, opcode)

Fixed for both stackman_switch (two calls) and stackman_call.
---
 stackman/platforms/switch_riscv64_gcc.S | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/stackman/platforms/switch_riscv64_gcc.S b/stackman/platforms/switch_riscv64_gcc.S
index 8f990c7..54d97c1 100644
--- a/stackman/platforms/switch_riscv64_gcc.S
+++ b/stackman/platforms/switch_riscv64_gcc.S
@@ -99,20 +99,20 @@ LABEL(stackman_switch)
 	mv	s2, a0		/* s2 = callback */
 	mv	s3, a1		/* s3 = context */
 	
-	/* First callback: callback(context, sp, 0) */
+	/* First callback: callback(context, opcode, sp) */
 	mv	a0, s3		/* a0 = context */
-	mv	a1, sp		/* a1 = current sp */
-	li	a2, 0		/* a2 = 0 (first call) */
+	li	a1, 0		/* a1 = STACKMAN_OP_SAVE */
+	mv	a2, sp		/* a2 = current sp */
 	jalr	s2		/* call callback */
 	
 	/* Save returned pointer and switch stack */
 	mv	s4, a0		/* s4 = returned value */
 	mv	sp, a0		/* switch to new stack */
 	
-	/* Second callback: callback(context, new_sp, 1) */
+	/* Second callback: callback(context, opcode, sp) */
 	mv	a0, s3		/* a0 = context */
-	mv	a1, sp		/* a1 = new sp */
-	li	a2, 1		/* a2 = 1 (second call) */
+	li	a1, 1		/* a1 = STACKMAN_OP_RESTORE */
+	mv	a2, sp		/* a2 = new sp */
 	jalr	s2		/* call callback */
 	
 	/* Restore callee-saved floating point registers */
@@ -200,10 +200,10 @@ LABEL(stackman_call)
 	mv	t1, a2			/* t1 = new_stack (for arg) */
 	mv	sp, a2			/* switch to new stack */
 	
-	/* Call callback(context, new_stack, 0) */
+	/* Call callback(context, opcode, sp) */
 	mv	a0, a1			/* a0 = context */
-	mv	a1, t1			/* a1 = new_stack */
-	li	a2, 0			/* a2 = 0 */
+	li	a1, 2			/* a1 = STACKMAN_OP_CALL */
+	mv	a2, t1			/* a2 = new_stack */
 	jalr	t0			/* call callback */
 	
 	/* Restore old stack pointer from s0 */

From 3ff65d555c407d2a678ed1593b6a634205f289d2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kristj=C3=A1n=20Valur=20J=C3=B3nsson?= <sweskman@gmail.com>
Date: Sun, 16 Nov 2025 18:38:04 +0000
Subject: [PATCH 13/15] Update documentation for RISC-V support

- Bump version to 1.2.0
- Add riscv64 to supported platforms list in README
- Add v1.2.0 changelog entry with RISC-V details
---
 CHANGELOG.md | 16 ++++++++++++++++
 README.md    |  3 ++-
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6cb1f4a..495227c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,22 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [1.2.0] - 2025-11-16
+
+### Added
+- RISC-V platform support
+  - `riscv64` - RISC-V 64-bit (LP64D ABI with hardware double-precision floating point)
+- Platform detection for RISC-V in `platforms/platform.h` using `__riscv` and `__riscv_xlen` macros
+- Assembly implementation in `platforms/switch_riscv64_gcc.S`
+  - Full register preservation (s0-s11, fs0-fs11, ra)
+  - 16-byte stack alignment per RISC-V ABI
+  - Both `stackman_switch` and `stackman_call` functions
+- RISC-V build job in CI workflow with qemu-riscv64 emulation
+- RISC-V library included in release archives
+
+### Changed
+- Release archives now contain 10 platform libraries (was 9)
+
 ## [1.1.0] - 2025-11-16
 
 ### Added
diff --git a/README.md b/README.md
index eab378a..abee91c 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
 
 # stackman
 
-**Version 1.1.0**
+**Version 1.2.0**
 
 Simple low-level stack manipulation API and implementation for common platforms
 
@@ -80,6 +80,7 @@ calling convention, plus archive format:
    - sysv_amd64 (64-bit x86_64)
    - arm32 (32-bit ARM, AAPCS)
    - aarch64 (64-bit ARM, AAPCS64)
+   - riscv64 (64-bit RISC-V, LP64D ABI)
  - **macOS (Darwin)**
    - darwin_x86_64 (Intel)
    - darwin_arm64 (Apple Silicon)

From df2b54f232b8e305b891103a1e8d4c185f0ce605 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kristj=C3=A1n=20Valur=20J=C3=B3nsson?= <sweskman@gmail.com>
Date: Sun, 16 Nov 2025 18:38:54 +0000
Subject: [PATCH 14/15] Remove temporary RISC-V test workflow

RISC-V is now part of the main buildcommit.yml workflow.
---
 .github/workflows/riscv-test.yml | 52 --------------------------------
 1 file changed, 52 deletions(-)
 delete mode 100644 .github/workflows/riscv-test.yml

diff --git a/.github/workflows/riscv-test.yml b/.github/workflows/riscv-test.yml
deleted file mode 100644
index f8d7805..0000000
--- a/.github/workflows/riscv-test.yml
+++ /dev/null
@@ -1,52 +0,0 @@
-name: RISC-V Test Build
-
-on:
-  push:
-    branches: [ riscv-support ]
-  pull_request:
-    branches: [ master ]
-    paths:
-      - 'stackman/platforms/switch_riscv64_gcc.*'
-      - 'stackman/platforms/platform.h'
-      - '.github/workflows/riscv-test.yml'
-
-jobs:
-
-  build-riscv64:
-    runs-on: ubuntu-latest
-    
-    steps:
-    - uses: actions/checkout@v4
-    
-    - name: Install RISC-V toolchain and QEMU
-      run: |
-        sudo apt-get update
-        sudo apt-get install --no-install-recommends -y \
-          gcc-riscv64-linux-gnu \
-          g++-riscv64-linux-gnu \
-          qemu-user
-    
-    - name: Show toolchain info
-      run: |
-        riscv64-linux-gnu-gcc --version
-        qemu-riscv64 --version
-    
-    - name: Build library
-      env:
-        PLATFORM_PREFIX: riscv64-linux-gnu
-      run: make all
-    
-    - name: Show ABI name
-      run: make abiname
-    
-    - name: Run tests
-      env:
-        PLATFORM_PREFIX: riscv64-linux-gnu
-        EMULATOR: qemu-riscv64
-      run: make test
-    
-    - name: Upload library artifact
-      uses: actions/upload-artifact@v4
-      with:
-        name: riscv64-test-build
-        path: lib/riscv64/libstackman.a

From d225ab7ed551385eb614093a20ac9ddfc0854fe8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kristj=C3=A1n=20Valur=20J=C3=B3nsson?= <sweskman@gmail.com>
Date: Sun, 16 Nov 2025 18:39:35 +0000
Subject: [PATCH 15/15] Bump version to 1.2.0 in header file

---
 stackman/stackman.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/stackman/stackman.h b/stackman/stackman.h
index 483c1e9..257ec54 100644
--- a/stackman/stackman.h
+++ b/stackman/stackman.h
@@ -4,11 +4,11 @@
 
 /* Version information */
 #define STACKMAN_VERSION_MAJOR 1
-#define STACKMAN_VERSION_MINOR 1
+#define STACKMAN_VERSION_MINOR 2
 #define STACKMAN_VERSION_PATCH 0
 
 /* Version as a string */
-#define STACKMAN_VERSION "1.1.0"
+#define STACKMAN_VERSION "1.2.0"
 
 /* Version as a single number for comparisons (MMmmpp: Major, minor, patch) */
 #define STACKMAN_VERSION_NUMBER ((STACKMAN_VERSION_MAJOR * 10000) + \