From: Niklas Haas <g...@haasn.dev>
Generic helper macros to push/pop multiple registers at once. Expands to
a single `addi` plus a sequence of XLEN-sized stores/loads.
---
libavutil/riscv/asm.S | 37 +++++++++++++++++++++++++++++++++++++
1 file changed, 37 insertions(+)
diff --git a/libavutil/riscv/asm.S b/libavutil/riscv/asm.S
index db190e99ca..3955530e4e 100644
--- a/libavutil/riscv/asm.S
+++ b/libavutil/riscv/asm.S
@@ -288,3 +288,40 @@
.macro count_args args:vararg
count_args_inner 0, \args
.endm
+
+ /**
+ * Helper macro to iterate over constant sized elements in memory
+ * @param op operation to perform on each element (sized load/store)
+ * @param size size in bytes per element
+ * @param offset starting offset of first element
+ * @param addr base address to load/store
+ * @param regs registers to iterate over
+ */
+ .macro for_mem op, size, offset, addr, reg, regs:vararg
+ .ifnb \reg
+ \op \reg, \offset(\addr)
+ for_mem \op, \size, \offset + \size, \addr, \regs
+ .endif
+ .endm
+
+ /**
+ * Push a variable number of registers to the stack.
+ * @param n number of registers to push
+ * @param regs registers to push
+ */
+ .macro push regs:vararg
+ count_args \regs
+ addi sp, sp, -(num_args * (__riscv_xlen >> 3))
+ for_mem sx, __riscv_xlen >> 3, 0, sp, \regs
+ .endm
+
+ /**
+ * Pop a variable number of registers from the stack.
+ * @param n number of registers to pop
+ * @param[out] regs registers to pop
+ */
+ .macro pop regs:vararg
+ count_args \regs
+ for_mem lx, __riscv_xlen >> 3, 0, sp, \regs
+ addi sp, sp, num_args * (__riscv_xlen >> 3)
+ .endm
--
2.45.1
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